JP4793632B2 - Metal oxide nanoporous material, catalyst support, and catalyst for hydrogen generation reaction using the same - Google Patents
Metal oxide nanoporous material, catalyst support, and catalyst for hydrogen generation reaction using the same Download PDFInfo
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- JP4793632B2 JP4793632B2 JP2006004086A JP2006004086A JP4793632B2 JP 4793632 B2 JP4793632 B2 JP 4793632B2 JP 2006004086 A JP2006004086 A JP 2006004086A JP 2006004086 A JP2006004086 A JP 2006004086A JP 4793632 B2 JP4793632 B2 JP 4793632B2
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- 229910044991 metal oxide Inorganic materials 0.000 title claims description 246
- 150000004706 metal oxides Chemical class 0.000 title claims description 246
- 239000003054 catalyst Substances 0.000 title claims description 67
- 239000007783 nanoporous material Substances 0.000 title description 78
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title description 29
- 239000001257 hydrogen Substances 0.000 title description 29
- 229910052739 hydrogen Inorganic materials 0.000 title description 29
- 238000006243 chemical reaction Methods 0.000 title description 18
- 238000005259 measurement Methods 0.000 claims description 148
- 238000000576 coating method Methods 0.000 claims description 124
- 239000011248 coating agent Substances 0.000 claims description 121
- 229910052751 metal Inorganic materials 0.000 claims description 87
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 76
- 239000000843 powder Substances 0.000 claims description 74
- 239000000758 substrate Substances 0.000 claims description 67
- 239000000203 mixture Substances 0.000 claims description 51
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 41
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 41
- 239000012530 fluid Substances 0.000 claims description 40
- 239000002245 particle Substances 0.000 claims description 38
- 239000002994 raw material Substances 0.000 claims description 38
- 239000000523 sample Substances 0.000 claims description 36
- 239000012266 salt solution Substances 0.000 claims description 35
- 238000002156 mixing Methods 0.000 claims description 33
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 32
- 229910000510 noble metal Inorganic materials 0.000 claims description 20
- 239000008199 coating composition Substances 0.000 claims description 15
- 239000000084 colloidal system Substances 0.000 claims description 13
- 238000010894 electron beam technology Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 13
- 238000002407 reforming Methods 0.000 claims description 13
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- 238000004458 analytical method Methods 0.000 claims description 9
- 150000000703 Cerium Chemical class 0.000 claims description 5
- 238000000635 electron micrograph Methods 0.000 claims description 5
- 239000011800 void material Substances 0.000 claims description 5
- 150000003754 zirconium Chemical class 0.000 claims description 5
- 238000010079 rubber tapping Methods 0.000 claims description 4
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 82
- 239000002184 metal Substances 0.000 description 63
- 230000000052 comparative effect Effects 0.000 description 58
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- 239000000463 material Substances 0.000 description 30
- 238000001035 drying Methods 0.000 description 29
- 241000264877 Hippospongia communis Species 0.000 description 27
- 238000010304 firing Methods 0.000 description 24
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 20
- 238000000975 co-precipitation Methods 0.000 description 19
- 238000012360 testing method Methods 0.000 description 18
- 239000010408 film Substances 0.000 description 17
- 238000004519 manufacturing process Methods 0.000 description 17
- 239000007787 solid Substances 0.000 description 16
- 239000010409 thin film Substances 0.000 description 16
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 15
- 230000005540 biological transmission Effects 0.000 description 15
- 229910052782 aluminium Inorganic materials 0.000 description 14
- 239000002131 composite material Substances 0.000 description 14
- 239000007809 chemical reaction catalyst Substances 0.000 description 13
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 13
- 239000011148 porous material Substances 0.000 description 12
- 229910052726 zirconium Inorganic materials 0.000 description 12
- 229910052684 Cerium Inorganic materials 0.000 description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 11
- 239000007789 gas Substances 0.000 description 11
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 10
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 9
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- 229910052878 cordierite Inorganic materials 0.000 description 7
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 7
- 238000009826 distribution Methods 0.000 description 7
- 238000010298 pulverizing process Methods 0.000 description 7
- 229910052703 rhodium Inorganic materials 0.000 description 6
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 6
- 238000001179 sorption measurement Methods 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 238000003917 TEM image Methods 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 238000000921 elemental analysis Methods 0.000 description 5
- 229910052763 palladium Inorganic materials 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 4
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- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000000790 scattering method Methods 0.000 description 4
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 239000012046 mixed solvent Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 230000001464 adherent effect Effects 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 150000004696 coordination complex Chemical class 0.000 description 2
- JVSWJIKNEAIKJW-UHFFFAOYSA-N dimethyl-hexane Natural products CCCCCC(C)C JVSWJIKNEAIKJW-UHFFFAOYSA-N 0.000 description 2
- 239000002612 dispersion medium Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- UJVRJBAUJYZFIX-UHFFFAOYSA-N nitric acid;oxozirconium Chemical compound [Zr]=O.O[N+]([O-])=O.O[N+]([O-])=O UJVRJBAUJYZFIX-UHFFFAOYSA-N 0.000 description 2
- 229910052762 osmium Inorganic materials 0.000 description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 238000004506 ultrasonic cleaning Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- BNUDRLITYNMTPD-UHFFFAOYSA-N acetic acid;zirconium Chemical compound [Zr].CC(O)=O BNUDRLITYNMTPD-UHFFFAOYSA-N 0.000 description 1
- 239000002156 adsorbate Substances 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000006059 cover glass Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 229910021432 inorganic complex Inorganic materials 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 230000000051 modifying effect Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 238000002429 nitrogen sorption measurement Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000012255 powdered metal Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 1
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- 230000003068 static effect Effects 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 230000005469 synchrotron radiation Effects 0.000 description 1
- CENHPXAQKISCGD-UHFFFAOYSA-N trioxathietane 4,4-dioxide Chemical compound O=S1(=O)OOO1 CENHPXAQKISCGD-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Description
本発明は、水素生成反応用の触媒の担体等として有効な金属酸化物ナノ多孔体及び触媒担体、並びにその触媒担体を用いた水素生成反応用触媒に関する。 The present invention relates to a metal oxide nanoporous material and a catalyst carrier that are effective as a catalyst carrier for a hydrogen production reaction, and a hydrogen production reaction catalyst using the catalyst carrier.
従来、燃料電池等の燃料改質システムにおいて燃料となる水素を生成させるための水素生成反応用触媒として様々な触媒が開発されており、そのような水素生成反応用触媒としてはハニカムフィルタ等の各種基材にアルミナ等の金属酸化物と白金、ロジウム、パラジウム等の貴金属とを担持せしめたもの等が一般的に使用されている。 Conventionally, various catalysts have been developed as hydrogen generation reaction catalysts for generating hydrogen as a fuel in fuel reforming systems such as fuel cells. As such hydrogen generation reaction catalysts, various types of catalysts such as honeycomb filters have been developed. In general, a substrate in which a metal oxide such as alumina and a noble metal such as platinum, rhodium, and palladium are supported is used.
そして、従来は、このような金属酸化物として湿式粉砕法によって得られた粉末が一般的に使用されており、例えば特開平１０−１８２１５５号公報（特許文献１）や特開２００２−７９０９７号公報（特許文献２）には、アルミニウム、セリウム及びジルコニウムの塩溶液から共沈法により酸化物前駆体を調製し、それを大気中で焼成することによって複合金属酸化物の粉末を得る方法が開示されている。また、特開平７−３００３１５号公報（特許文献３）には、セリウム塩水溶液及びジルコニウム塩水溶液を混合した混合溶液にベーマイトアルミナ粉末を加えて攪拌した後に乾燥及び焼成することによって複合金属酸化物の粉末を得る方法が開示されている。 Conventionally, a powder obtained by a wet pulverization method as such a metal oxide is generally used. For example, Japanese Patent Application Laid-Open No. 10-182155 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-79097. (Patent Document 2) discloses a method of obtaining a composite metal oxide powder by preparing an oxide precursor from a salt solution of aluminum, cerium and zirconium by a coprecipitation method and firing the precursor in the air. ing. JP-A-7-300315 (Patent Document 3) discloses a composite metal oxide by adding boehmite alumina powder to a mixed solution obtained by mixing an aqueous cerium salt solution and an aqueous zirconium salt solution, followed by drying and firing. A method for obtaining a powder is disclosed.
しかしながら、上記特許文献１〜３に記載のような従来の金属酸化物の粉末を用いた場合においては、基材（特に金属基材）に対する付着性や耐熱性が未だ必ずしも十分なものではなく、基材上に形成する被覆の薄膜化にも限界があるため、金属製のハニカムフィルタや、一般的なハニカムフィルタより狭い管状通路を有する高密度ハニカム（例えば、１２００cell／inch２以上のマイクロチャンネル）等の基材に対してはこのような従来の金属酸化物の粉末を担持させることは困難であり、改質特性の向上にも限界があるという問題があった。
本発明は、上記従来技術の有する課題に鑑みてなされたものであり、ハニカムフィルタ等の各種基材に対して付着性が高く且つ優れた耐熱性を有しており、更に基材上に形成する被覆の薄膜化も可能であり、金属製のハニカムフィルタや高密度ハニカム等の基材に対しても高水準の付着性をもって優れた耐熱性を有する被覆を形成することが可能な金属酸化物ナノ多孔体、並びにそれを用いた水素生成反応における改質特性を十分に向上させることが可能な触媒担体及び水素生成反応用触媒を提供することを目的とする。 The present invention has been made in view of the above-described problems of the prior art, has high adhesion to various substrates such as honeycomb filters, and has excellent heat resistance, and is further formed on the substrate. Metal oxide that can form a coating with excellent heat resistance with a high level of adhesion to substrates such as metallic honeycomb filters and high density honeycombs It is an object of the present invention to provide a nanoporous body, a catalyst support capable of sufficiently improving reforming characteristics in a hydrogen generation reaction using the nanoporous body, and a hydrogen generation reaction catalyst.
本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、金属酸化物のコロイド溶液や金属塩の溶液をそのまま用いて得られる金属酸化物の被覆は不均一で付着性及び耐熱性も十分なものではないのに対して、金属酸化物のコロイド溶液や金属塩の溶液を高剪断速度の下で混合し、実質的に共沈させることなく熱処理するようにすると、驚くべきことに得られる金属酸化物は直径が１０ｎｍ以下のナノ細孔を有し且つナノ細孔を構成する壁体において金属酸化物が均質に分散している従来にない新規なものとなり、各種基材に対する付着性及び耐熱性が向上し、更に薄膜化も可能となり、かかる被覆を構成する成分をジルコニア及びセリアを特定量含有するジルコニア／セリア２成分系又はジルコニア、セリア及びアルミナを特定量含有するジルコニア／セリア／アルミナ３成分系とすることによって水素生成反応における改質特性が非常に優れた水素生成反応用触媒が得られるようになることを見出し、本発明を完成するに至った。 As a result of intensive studies to achieve the above object, the present inventors have found that the metal oxide coating obtained by using a metal oxide colloidal solution or a metal salt solution as it is is non-uniform, adherent and heat resistant. However, it is surprising that metal oxide colloidal solutions and metal salt solutions are mixed at high shear rates and heat treated without substantial coprecipitation. The resulting metal oxide has nanopores with a diameter of 10 nm or less and the metal oxide is homogeneously dispersed in the wall constituting the nanopore, which is an unprecedented novel and adheres to various substrates. The heat and heat resistance is improved, and further thinning is possible, and the components constituting this coating are zirconia / ceria two-component system containing specific amounts of zirconia and ceria, or specific amounts of zirconia, ceria and alumina. That zirconia / ceria / alumina 3 found that so modifying properties are very good hydrogen production reaction catalyst obtained in the hydrogen production reaction by the component system, thereby completing the present invention.
本発明の触媒担体は、基材と、前記基材の表面上に形成された２種以上の金属酸化物により構成される被覆とを備える触媒担体であって、前記被覆におけるセリアの含有量が１０〜６０質量％、ジルコニアの含有量が２０〜９０質量％、アルミナの含有量が７０質量％以下であり、
前記被覆に１０ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザーを用いて０．５ｍｍ以上の範囲を任意に線分析して求めた下記式（２）：
Ｋ値（％）＝（被覆から検出されたＸ線強度）／（純物質から得られるＸ線強度）
で表されるＫ値が、前記金属元素のすべてについて、全測定点のうちの６５％以上の測定点において下記式（３）：
で表される条件を満たしていることを特徴とする燃料改質用触媒担体である。
The catalyst carrier of the present invention is a catalyst carrier comprising a substrate and the covered bets that is composed of two or more metal oxide formed on the surface of the substrate, the content of ceria in the coating 10 to 60 mass%, the content of zirconia is 20 to 90 mass%, the content of alumina is 70 mass% or less,
The metal elements of all the metal oxides contained in the coating in an amount of 10 at% or more were obtained by arbitrarily performing a line analysis over a range of 0.5 mm or more using an X-ray microanalyzer having an acceleration voltage of 15 kV and an electron beam diameter of 1 μm. Following formula (2):
K value (%) = (X-ray intensity detected from coating) / (X-ray intensity obtained from pure substance)
The K value represented by the following formula (3) for all the metal elements at the measurement points of 65% or more of all the measurement points:
The catalyst carrier for fuel reforming characterized by satisfying the condition expressed by
前記被覆は、ジルコニアコロイド粒子及び／又はジルコニウム塩溶液と、セリアコロイド粒子及び／又はセリウム塩溶液とを含有する原料流体組成物を、１００００ｓｅｃ−１以上の剪断速度の下で混合して得た被覆組成物を直ちに前記基材に塗布した後に熱処理して得たものであることが好ましく、前記原料流体組成物中にアルミナコロイド粒子及び／又はアルミニウム塩溶液が更に含有されていてもよい。 The coating was obtained by mixing a raw fluid composition containing zirconia colloid particles and / or zirconium salt solution and ceria colloid particles and / or cerium salt solution under a shear rate of 10,000 sec −1 or more . The coating composition is preferably obtained by immediately applying the coating composition to the substrate and then heat-treating, and the raw material fluid composition may further contain alumina colloidal particles and / or an aluminum salt solution.
また、前記被覆中に、平均粒径が０．０１〜５０μｍであるジルコニア粉末、セリア粉末及びアルミナ粉末からなる群から選択される少なくとも一つの粉末が更に含有されていてもよい。 The coating may further contain at least one powder selected from the group consisting of zirconia powder, ceria powder and alumina powder having an average particle diameter of 0.01 to 50 μm.
さらに、前記ナノ多孔体においては、下記の条件(I)〜(II)のうちの少なくとも一つが満たされていることがより好ましい。 Furthermore, in the nanoporous material, it is more preferable that at least one of the following conditions (I) to (II) is satisfied.
(I)走査型プローブ顕微鏡にて５ｎｍの曲率半径を有するチップを用いて、３ｎｍ以上４ｎｍ未満の間隔で前記被覆の表面の高さ像をタッピングモードで任意に計測し、総計で２μｍ以上の走査距離Ｌの関数として求めた高さ像Ｈ（Ｌ）が、全測定点のうちの８０％以上の測定点において下記式（４）：
Ｈ（Ｌ）≦２０ｎｍ （４）
［式（４）中、Ｈ（Ｌ）は各測定点（走査距離＝Ｌ）における高さ像（ｎｍ）を示す。但し、全測定点における高さ像Ｈの平均値を零とする。］
で表される条件を満たしており、且つ、下記式（５）及び（６）：
(I) Using a tip having a radius of curvature of 5 nm with a scanning probe microscope, the surface height image of the coating is arbitrarily measured in a tapping mode at intervals of 3 nm or more and less than 4 nm, and the total scanning is 2 μm or more. When the height image H (L) obtained as a function of the distance L is 80% or more of all the measurement points, the following formula (4):
H (L) ≦ 20nm (4)
[In Expression (4), H (L) represents a height image (nm) at each measurement point (scanning distance = L). However, the average value of the height image H at all measurement points is set to zero. ]
And the following formulas (5) and (6):
［式（５）及び（６）中、Ｈ（Ｌ）は走査距離＝Ｌの測定点における高さ像（ｎｍ）、Ｈ（Ｌ＋ΔＬ）は走査距離＝Ｌ＋ΔＬの測定点における高さ像（ｎｍ）、ΔＬは測定点の間隔（ｎｍ）、Ｈ’（Ｌ）は高さ像Ｈ（Ｌ）の一次微係数、Ｈ’（Ｌ＋ΔＬ）は高さ像Ｈ（Ｌ＋ΔＬ）の一次微係数、Ｈ”（Ｌ）は高さ像Ｈ（Ｌ）の二次微係数をそれぞれ示す。但し、ΔＬは測定点間の直線補間により４ｎｍとする。］
により求めた二次微係数Ｈ”（Ｌ）が、全測定点のうちの６０％以下の測定点において下記式（７）：
−０．０５ｎｍ−１≦Ｈ”（Ｌ）≦０．０５ｎｍ−１ （７）
で表される条件を満たしていること。
[In formulas (5) and (6), H (L) is the height image (nm) at the measurement point where the scanning distance = L, and H (L + ΔL) is the height image (nm) at the measurement point where the scanning distance = L + ΔL. , ΔL is the measurement point interval (nm), H ′ (L) is the first derivative of the height image H (L), H ′ (L + ΔL) is the first derivative of the height image H (L + ΔL), and H ″ ( L) represents the second derivative of the height image H (L), where ΔL is 4 nm by linear interpolation between measurement points.]
The second differential coefficient H ″ (L) obtained by the following equation (7) at the measurement points of 60% or less of all the measurement points:
−0.05 nm −1 ≦ H ″ (L) ≦ 0.05 nm −1 (7)
The condition represented by is satisfied.
(II)前記被覆の断面の電子顕微鏡写真において、前記被覆の上に任意に総計で４００μｍ以上の測定直線を描いた際に、前記測定直線が前記被覆に形成されている空隙部と交差している部分の長さの比率が、前記測定直線の全長の１０％以下であるという条件を満たしていること。 (II) in an electron micrograph of a cross-section of the coating, when depicting the 400μm or more measured linearly in total to any on of the coating, and intersects the void portion in which the measuring linearity is formed in said cover The ratio of the length of the portion being present satisfies the condition that it is 10% or less of the total length of the measurement straight line.
また、本発明の燃料改質用触媒は、前記本発明の触媒担体と、前記触媒担体の表面に担持される貴金属とを備えることを特徴とするものである。 The fuel reforming catalyst of the present invention comprises the catalyst carrier of the present invention and a noble metal supported on the surface of the catalyst carrier.
本発明によれば、ハニカムフィルタ等の各種基材に対して付着性が高く且つ優れた耐熱性を有しており、更に基材上に形成する被覆の薄膜化も可能であり、金属製のハニカムフィルタや高密度ハニカム等の基材に対しても高水準の付着性をもって優れた耐熱性を有する被覆を形成することが可能な金属酸化物ナノ多孔体、並びにそれを用いた水素生成反応における改質特性を十分に向上させることが可能な触媒担体及び水素生成反応用触媒を提供することが可能となる。 According to the present invention, it has high adhesion to various substrates such as honeycomb filters and has excellent heat resistance, and it is also possible to reduce the thickness of the coating formed on the substrate. Metal oxide nanoporous material capable of forming a coating having excellent heat resistance with a high level of adhesion to a substrate such as a honeycomb filter or a high-density honeycomb, and a hydrogen generation reaction using the metal oxide nanoporous material It is possible to provide a catalyst carrier and a hydrogen generation reaction catalyst that can sufficiently improve the reforming characteristics.
以下、本発明をその好適な実施形態に即して詳細に説明する。先ず、本発明の金属酸化物ナノ多孔体及びそれを用いた触媒担体について説明する。 Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof. First, the metal oxide nanoporous material of the present invention and a catalyst carrier using the same will be described.
すなわち、本発明の金属酸化物ナノ多孔体は、２種以上の金属酸化物により構成される金属酸化物ナノ多孔体であって、前記ナノ多孔体におけるセリアの含有量が１０〜６０質量％、ジルコニアの含有量が２０〜９０質量％、アルミナの含有量が７０質量％以下であり、前記ナノ多孔体は直径が１０ｎｍ以下のナノ細孔を有しており、且つ、前記ナノ細孔を構成する壁体において前記金属酸化物が均質に分散していることを特徴とするものである。 That is, the metal oxide nanoporous material of the present invention is a metal oxide nanoporous material composed of two or more metal oxides, and the content of ceria in the nanoporous material is 10 to 60% by mass, The zirconia content is 20 to 90% by mass, the alumina content is 70% by mass or less, the nanoporous body has nanopores having a diameter of 10 nm or less, and constitutes the nanopores. In the wall body, the metal oxide is uniformly dispersed.
また、本発明の触媒担体は、基材と、前記基材の表面上に形成された前記本発明の金属酸化物ナノ多孔体からなる被覆とを備えることを特徴とするものである。 The catalyst carrier of the present invention comprises a base material and a coating made of the metal oxide nanoporous material of the present invention formed on the surface of the base material.
本発明にかかる金属酸化物ナノ多孔体がジルコニア／セリア２成分系の場合、セリアの含有量は１０〜６０質量％、ジルコニアの含有量は４０〜９０質量％であることがより好ましい。セリアの含有量が上記下限未満では、特に低温における転化率が低く、達成される水素濃度も十分に向上しない。他方、セリアの含有量が上記上限を超えると、各種基材に対する付着性が低くなる。 When the metal oxide nanoporous material according to the present invention is a zirconia / ceria two-component system, the ceria content is more preferably 10 to 60% by mass, and the zirconia content is more preferably 40 to 90% by mass. If the ceria content is less than the above lower limit, the conversion rate is particularly low at low temperatures, and the hydrogen concentration achieved is not sufficiently improved. On the other hand, when the content of ceria exceeds the above upper limit, adhesion to various base materials is lowered.
また、発明にかかる金属酸化物ナノ多孔体がジルコニア／セリア／アルミナ３成分系の場合、セリアの含有量が上記下限未満では、特に低温における転化率が低く、達成される水素濃度も十分に向上しない。他方、セリアの含有量が上記上限を超えると、各種基材に対する付着性が低くなる。また、アルミナの含有量が上記上限を超えると、特に低温における転化率が低く、達成される水素濃度も十分に向上せず、アルミナの含有量が５０質量％以下であると、低温における転化率及び達成される水素濃度がより向上する傾向にあり好ましい。 Further, when the metal oxide nanoporous material according to the invention is a zirconia / ceria / alumina ternary system, when the ceria content is less than the above lower limit, the conversion rate is particularly low at a low temperature, and the achieved hydrogen concentration is sufficiently improved. do not do. On the other hand, when the content of ceria exceeds the above upper limit, adhesion to various base materials is lowered. If the alumina content exceeds the above upper limit, the conversion rate is particularly low at low temperatures, the hydrogen concentration achieved is not sufficiently improved, and if the alumina content is 50% by mass or less, the conversion rate at low temperatures. And the hydrogen concentration achieved tends to be further improved, which is preferable.
本発明の金属酸化物ナノ多孔体は、前述の金属酸化物により構成される多孔体であって、直径が１０ｎｍ以下のナノ細孔を有しており、且つ、前記ナノ細孔を構成する壁体において前記金属酸化物が均質に分散していることを特徴とするものである。 The metal oxide nanoporous material of the present invention is a porous material composed of the above-described metal oxide, and has nanopores having a diameter of 10 nm or less, and the walls constituting the nanopores The metal oxide is uniformly dispersed in the body.
このように、本発明の金属酸化物ナノ多孔体は、直径が１０ｎｍ以下、好ましくは５ｎｍ以下、より好ましくは２ｎｍ以下、という非常に微細な細孔を有しており、それによってこのような細孔を有さない金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性の向上が可能となり、さらに比表面積の向上や貴金属等の担持安定性の向上によって触媒担体等としての性能の向上が達成される。 As described above, the metal oxide nanoporous material of the present invention has very fine pores having a diameter of 10 nm or less, preferably 5 nm or less, more preferably 2 nm or less. Compared to porous metal oxides that do not have pores, it is possible to improve adhesion and heat resistance to various substrates, and further improve the performance as a catalyst support etc. by improving the specific surface area and the support stability of noble metals etc. Improvement is achieved.
また、本発明の金属酸化物ナノ多孔体においては、ナノ細孔を構成する壁体において前記金属酸化物が均質に分散している。すなわち、本発明の金属酸化物ナノ多孔体においては、ナノ多孔体を構成する２種以上の金属酸化物が実質的に原子レベルで均一に分散（高分散）していると考えられ、共沈法等によって得られた従来の金属酸化物多孔体のように各金属酸化物からなる１００ｎｍ程度の一次粒子が混合した状態や、一方の金属酸化物からなる一次粒子の表面を他方の金属酸化物が被覆している状態とは明らかに相違するものである。このような極めて高水準の成分均一性は、金属酸化物のコロイド溶液や金属塩の溶液をそのまま用いて得られる金属酸化物では決して得られるものではなく、２種以上の金属酸化物を含有するコロイド溶液や２種以上の金属塩を含有する溶液を高剪断速度の下で混合し、実質的に共沈させることなく熱処理する後述の製造方法によってはじめて達成されたものである。そして、このような極めて高水準の成分均一性を有する本発明の金属酸化物ナノ多孔体においては、驚くべきことに、共沈法等によって得られた従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が飛躍的に向上している。 In the metal oxide nanoporous material of the present invention, the metal oxide is uniformly dispersed in the wall constituting the nanopore. That is, in the metal oxide nanoporous material of the present invention, it is considered that two or more kinds of metal oxides constituting the nanoporous material are substantially uniformly dispersed (highly dispersed) at the atomic level. As in the conventional metal oxide porous body obtained by the method, etc., the state where primary particles of about 100 nm composed of each metal oxide are mixed, or the surface of the primary particle composed of one metal oxide is the other metal oxide This is clearly different from the state of covering. Such a very high level of component uniformity is never obtained with a metal oxide obtained by using a metal oxide colloidal solution or a metal salt solution as it is, and contains two or more metal oxides. This is achieved for the first time by a production method described later in which a colloidal solution or a solution containing two or more metal salts is mixed at a high shear rate and heat-treated without substantial coprecipitation. And surprisingly, in the metal oxide nanoporous material of the present invention having such a very high level of component uniformity, various kinds of metal oxide nanoporous materials obtained by a coprecipitation method or the like are various. Adhesion to the base material and heat resistance are dramatically improved.
本発明の金属酸化物ナノ多孔体の形状は特に制限されず、薄膜状であっても、粉末状であってもよく、それらを所定の形状に成形した成形体であってもよい。本発明の金属酸化物ナノ多孔体が薄膜状の場合、その厚さは特に制限されず、その用途等に応じて適宜調整される。また、本発明の触媒担体において前記基材の表面上に形成される前記被覆の厚さは特に制限されず、用いる基材や得られる触媒の用途等に応じて適宜調整されるが、本発明の金属酸化物ナノ多孔体は薄くした場合であっても金属製ハニカムフィルタ等の各種基材に対して付着性に優れた均一な被覆を形成することが可能であるため、被覆の厚さは１〜３００μｍ程度であることが好ましく、１〜５０μｍ程度であることがより好ましい。さらに、このように本発明によれば前記基材の表面上に形成する被覆の薄膜化が可能となるため、従来は十分な被覆を形成することが困難であった高密度ハニカムに対しても高水準の付着性をもって優れた耐熱性を有する被覆を形成することが可能となり、このような観点からは薄膜の厚さが１〜３０μｍ程度であることが特に好ましい。 The shape of the metal oxide nanoporous material of the present invention is not particularly limited, and may be a thin film shape, a powder shape, or a molded body obtained by molding them into a predetermined shape. When the metal oxide nanoporous material of the present invention is in the form of a thin film, the thickness thereof is not particularly limited, and is appropriately adjusted according to the application. Further, the thickness of the coating formed on the surface of the base material in the catalyst carrier of the present invention is not particularly limited, and is appropriately adjusted according to the base material used, the use of the obtained catalyst, and the like. Even if the metal oxide nanoporous material is thin, it is possible to form a uniform coating with excellent adhesion to various substrates such as a metal honeycomb filter, so the coating thickness is The thickness is preferably about 1 to 300 μm, and more preferably about 1 to 50 μm. Further, according to the present invention, since the coating formed on the surface of the substrate can be made thin, it is difficult to form a high density honeycomb which has been difficult to form a sufficient coating. It becomes possible to form a coating having excellent heat resistance with a high level of adhesion, and from this point of view, the thickness of the thin film is particularly preferably about 1 to 30 μm.
また、本発明の金属酸化物ナノ多孔体が粉末状の場合、その粒径は特に制限されず、その用途等に応じて適宜調整されるが、一般的には０．０１〜５０μｍ程度が好ましい。このような粉体の平均粒径が０．０１μｍ未満のものは金属酸化物の粉砕による製造法としては作製が困難であり、他方、５０μｍを超えると得られる被覆の厚みが非常に厚くなり、また付着性が低下するといった問題が発生する傾向にある。 In addition, when the metal oxide nanoporous material of the present invention is in a powder form, the particle size thereof is not particularly limited and is appropriately adjusted according to the use and the like, but generally about 0.01 to 50 μm is preferable. . Such a powder having an average particle size of less than 0.01 μm is difficult to produce as a manufacturing method by pulverization of metal oxide, and on the other hand, if it exceeds 50 μm, the resulting coating becomes very thick, In addition, there is a tendency for problems such as a decrease in adhesion.
このような本発明の金属酸化物ナノ多孔体は、
(i)ジルコニアコロイド粒子及び／又はジルコニウム塩溶液と、セリアコロイド粒子及び／又はセリウム塩溶液とを含有する原料流体組成物、或いは、
(ii)ジルコニアコロイド粒子及び／又はジルコニウム塩溶液と、セリアコロイド粒子及び／又はセリウム塩溶液と、アルミナコロイド粒子及び／又はアルミニウム塩溶液とを含有する原料流体組成物、
を１０００ｓｅｃ−１以上の剪断速度の下で混合した後、実質的に共沈させることなく熱処理して得たものである。
Such a metal oxide nanoporous material of the present invention is
(i) a raw material fluid composition containing zirconia colloidal particles and / or zirconium salt solution and ceria colloidal particles and / or cerium salt solution, or
(ii) a raw material fluid composition containing zirconia colloid particles and / or zirconium salt solution, ceria colloid particles and / or cerium salt solution, alumina colloid particles and / or aluminum salt solution,
Was mixed at a shear rate of 1000 sec −1 or higher and then heat-treated without substantial coprecipitation.
また、本発明の触媒担体における薄膜状の金属酸化物ナノ多孔体を得る場合、前記原料流体組成物を前記高速剪断速度の下で混合した後、実質的に共沈させることなく基材に塗布した後に熱処理する方法が好適に採用される。 Further, when obtaining a thin metal oxide nanoporous material in the catalyst carrier of the present invention, the raw material fluid composition is mixed under the high shear rate and then applied to the substrate without substantially coprecipitation. Then, a method of heat treatment is preferably employed.
本発明において用いられるジルコニア、セリア又はアルミナのコロイド粒子は、平均粒径が５〜２００ｎｍのコロイド粒子であり、好ましくは５〜１００ｎｍのコロイド粒子である。コロイド粒子の平均粒径が５ｎｍ未満のものについては、安定した粒子を作製することは困難であり、他方、２００ｎｍを超えると混合・分散性の低下、付着性の低下、反応性の低下等の種々の問題が発生する。なお、このようなコロイド粒子の形状は特に制限されず、針状粒子、棒状粒子、羽毛状粒子、球状粒子、不定形状粒子等のものが挙げられる。 The colloidal particles of zirconia, ceria or alumina used in the present invention are colloidal particles having an average particle size of 5 to 200 nm, preferably 5 to 100 nm. When the average particle size of colloidal particles is less than 5 nm, it is difficult to produce stable particles. On the other hand, when the average particle size exceeds 200 nm, mixing / dispersibility decreases, adhesion decreases, reactivity decreases, etc. Various problems occur. The shape of such colloidal particles is not particularly limited, and examples thereof include needle-shaped particles, rod-shaped particles, feather-shaped particles, spherical particles, and irregularly shaped particles.
また、本発明においては、前記ジルコニア、セリア又はアルミナのコロイド粒子と共に、或いはかかるコロイド粒子に代えて、ジルコニウム、セリウム又はアルミニウムの塩を用いてもよい。このような金属の塩としては、硝酸塩、酢酸塩、塩化物、硫酸塩、亜硫酸塩、無機錯塩等の水溶性の塩が好適に用いられ、例えば、硝酸アルミニウム、オキシ硝酸ジルコニウム、硝酸セリウム、酢酸ジルコニウム、オキシ硫酸ジルコニウムが挙げられる。 In the present invention, a salt of zirconium, cerium or aluminum may be used together with or instead of the colloidal particles of zirconia, ceria or alumina. As such metal salts, water-soluble salts such as nitrates, acetates, chlorides, sulfates, sulfites and inorganic complex salts are preferably used. For example, aluminum nitrate, zirconium oxynitrate, cerium nitrate, acetic acid Zirconium and zirconium oxysulfate are mentioned.
さらに、本発明にかかる前記原料流体組成物を調製するための溶媒としては、特に制限されず、水、アルコール（例えば、メタノール、エタノール、エチレングリコール等の単独又は混合系溶媒）等の各種溶媒が挙げられるが、金属基材への付着性向上という観点から水とアルコールとの混合溶媒が好ましく、アルコール含有量が４０〜１００質量％（特に好ましくは５５〜８０質量％）である水とアルコールとの混合溶媒が特に好ましい。また、本発明にかかる金属塩溶液のｐＨは、特に限定されるものではないが、溶液中で金属イオンがより安定に存在するという観点から、金属塩溶液のｐＨが３．０〜６．０であることが好ましい。 Furthermore, the solvent for preparing the raw material fluid composition according to the present invention is not particularly limited, and various solvents such as water, alcohol (for example, methanol, ethanol, ethylene glycol or the like alone or a mixed solvent) may be used. From the viewpoint of improving adhesion to a metal substrate, a mixed solvent of water and alcohol is preferable, and water and alcohol having an alcohol content of 40 to 100% by mass (particularly preferably 55 to 80% by mass) The mixed solvent is particularly preferred. Further, the pH of the metal salt solution according to the present invention is not particularly limited, but the pH of the metal salt solution is 3.0 to 6.0 from the viewpoint that metal ions are more stably present in the solution. It is preferable that
また、本発明においては、前記原料流体組成物中に、平均粒径が０．０１〜５０μｍ（好ましくは０．０１〜１０μｍ）であるジルコニア、セリア又はアルミナの粉末が更に含有されていてもよい。このような粉末の平均粒径が０．０１μｍ未満のものは金属酸化物の粉砕による製造法としては作製が困難であり、他方、５０μｍを超えると被覆の厚みが非常に厚くなり、また付着性が低下するといった問題が発生する傾向にある。なお、このような金属酸化物の粉末としては、金属塩を含有する溶液を乾燥した後に粉砕して得たものが好適に用いられる。さらに、その平均粒径は、得ようとする被覆の厚み以下であることが望ましい。 In the present invention, the raw material fluid composition may further contain a zirconia, ceria, or alumina powder having an average particle size of 0.01 to 50 μm (preferably 0.01 to 10 μm). . When the average particle size of such powder is less than 0.01 μm, it is difficult to produce as a manufacturing method by pulverizing metal oxide. On the other hand, when it exceeds 50 μm, the coating becomes very thick and adherent. There is a tendency for problems to occur. As such a metal oxide powder, a powder obtained by pulverizing a solution containing a metal salt after drying is suitably used. Furthermore, the average particle size is desirably equal to or less than the thickness of the coating to be obtained.
さらに、このような金属酸化物の粉末を用いる場合、その表面に貴金属を予め担持させておくこともできる。このような貴金属としては、白金、ロジウム、パラジウム、オスミウム、イリジウム、金等が挙げられ、中でも白金、ロジウム、パラジウムが好ましい。このような貴金属の担持量は特に制限されず、得られる触媒の用途等に応じて適宜調整されるが、得られる被覆を構成する金属酸化物１００質量部に対して０．１〜１０質量部程度となる量が一般的である。また、このような貴金属を担持させる具体的な方法も特に制限されないが、例えば、貴金属の塩（硝酸塩、塩化物、酢酸塩等）又は貴金属の錯体を水、アルコール等の溶媒に溶解した溶液に前記の粉末を浸漬し、溶媒を除去した後に焼成及び粉砕するといった方法が好適に用いられる。なお、前記貴金属を担持させる工程において溶媒を除去する際における乾燥条件としては３０〜１５０℃で１０分以内程度が好ましく、また、焼成条件としては、酸化雰囲気（例えば、空気）中において２５０〜３００℃で３０〜６０分程度が好ましい。また、所望の担持量になるまでこのような貴金属担持工程を繰り返してもよい。 Further, when such a metal oxide powder is used, a noble metal can be supported on the surface in advance. Examples of such noble metals include platinum, rhodium, palladium, osmium, iridium, gold and the like, among which platinum, rhodium and palladium are preferable. The amount of such noble metal supported is not particularly limited and is appropriately adjusted according to the use of the obtained catalyst, etc., but is 0.1 to 10 parts by mass with respect to 100 parts by mass of the metal oxide constituting the obtained coating. The amount to the extent is common. Further, a specific method for supporting such a noble metal is not particularly limited. For example, a noble metal salt (nitrate, chloride, acetate, etc.) or a noble metal complex dissolved in a solvent such as water or alcohol is used. A method of immersing the powder and removing the solvent, followed by firing and pulverization is preferably used. The drying condition for removing the solvent in the step of supporting the noble metal is preferably within 30 minutes at 30 to 150 ° C. The firing condition is 250 to 300 in an oxidizing atmosphere (for example, air). About 30 to 60 minutes are preferable at ° C. Moreover, you may repeat such a noble metal carrying | support process until it becomes a desired carrying amount.
本発明においては、前記原料流体組成物を１０００ｓｅｃ−１以上、より好ましくは１００００ｓｅｃ−１以上、特に好ましくは２００００ｓｅｃ−１以上、の剪断速度の下で混合して被覆組成物を得る。かかる剪断速度が１０００ｓｅｃ−１未満では、得られる金属酸化物ナノ多孔体が後述の成分均一性を満たすものにならず、その付着性及び耐熱性の十分な向上が得られない。なお、かかる剪断速度の上限は特に制限されないが、２０００００ｓｅｃ−１以下であることが好ましい。 In the present invention, the raw material fluid composition is mixed under a shear rate of 1000 sec −1 or more, more preferably 10,000 sec −1 or more, particularly preferably 20000 sec −1 or more to obtain a coating composition. When the shear rate is less than 1000 sec −1 , the obtained metal oxide nanoporous material does not satisfy the component uniformity described later, and sufficient improvement in adhesion and heat resistance cannot be obtained. The upper limit of the shear rate is not particularly limited, but is preferably 200,000 sec −1 or less.
なお、ここで用いる装置は、このような高剪断速度の下で混合できるものであればよく特に制限されないが、ホモジナイザが好適に用いられる。また、このような高剪断速度の下で混合する時間も特に制限されないが、１〜２０分（好ましくは１〜５分）程度が一般的である。 The apparatus used here is not particularly limited as long as it can be mixed at such a high shear rate, but a homogenizer is preferably used. Further, the mixing time under such a high shear rate is not particularly limited, but is generally about 1 to 20 minutes (preferably 1 to 5 minutes).
このような高剪断速度の下で混合される前記原料流体組成物の濃度（固形分濃度）は、目的とする金属酸化物ナノ多孔体の形状（厚みや粒径）、塗布や粉体化する方法に適した粘度等に応じて適宜調整されるが、５〜５０質量％程度の固形分濃度が一般的であり、好ましくは１０〜１５質量％程度の固形分濃度である。 The concentration (solid content concentration) of the raw material fluid composition mixed under such a high shear rate is the shape (thickness or particle size) of the target metal oxide nanoporous material, and is applied or powdered. Although it adjusts suitably according to the viscosity etc. which are suitable for a method, solid content concentration of about 5-50 mass% is common, Preferably it is about 10-15 mass% solid content concentration.
さらに、本発明においては、得られた原料流体組成物に混入している気泡を十分に除去するため、混合された原料流体組成物を１〜２分程度緩やかに攪拌（例えば、２０〜１００ｒｐｍ）する脱気処理を更に施してもよい。 Furthermore, in the present invention, in order to sufficiently remove bubbles mixed in the obtained raw material fluid composition, the mixed raw material fluid composition is gently stirred for about 1 to 2 minutes (for example, 20 to 100 rpm). The deaeration process to perform may be further performed.
以上説明した本発明にかかる原料流体組成物においては、前記のコロイド粒子及び／又は金属塩の諸成分が極めて均一に分散しており、このような原料流体組成物を実質的に共沈させることなく熱処理することによって、前述の本発明の金属酸化物ナノ多孔体が得られ、ハニカムフィルタ等の各種基材に対して付着性が高く且つ優れた耐熱性を有する前記金属酸化物の被覆を形成することが可能となり、更に基材上に形成する被覆の薄膜化も可能となる。そのため、本発明によれば、金属製のハニカムフィルタや高密度ハニカム等の基材に対しても高水準の付着性をもって優れた耐熱性を有する薄膜状の前記金属酸化物ナノ多孔体の被覆を均一に形成することが可能となる。 In the raw material fluid composition according to the present invention described above, the components of the colloidal particles and / or the metal salt are extremely uniformly dispersed, and the raw material fluid composition is substantially coprecipitated. The metal oxide nanoporous material of the present invention described above can be obtained by heat treatment without forming a coating of the metal oxide having high adhesion to various substrates such as a honeycomb filter and excellent heat resistance. It is also possible to reduce the thickness of the coating formed on the substrate. Therefore, according to the present invention, the coating of the metal oxide nanoporous body in the form of a thin film having a high level of adhesion and excellent heat resistance even on a substrate such as a metal honeycomb filter or a high-density honeycomb is provided. It becomes possible to form uniformly.
このように、本発明においては、原料流体組成物を実質的に共沈させることなく熱処理する必要がある。ここで、「実質的に共沈させることなく」とは、原料流体組成物中の金属元素が実質的に水酸化物を経ることなく熱処理によって固化して金属酸化物となることをいい、より具体的には、かかる熱処理前の原料流体組成物中の金属成分における水酸化物の比率が５０ａｔ％以下（より好ましくは３０ａｔ％以下）の場合をいう。 Thus, in this invention, it is necessary to heat-process, without substantially coprecipitating a raw material fluid composition. Here, “without substantially coprecipitation” means that the metal element in the raw material fluid composition is solidified by heat treatment without substantially passing through a hydroxide, and becomes a metal oxide. Specifically, it refers to the case where the ratio of hydroxide in the metal component in the raw material fluid composition before the heat treatment is 50 at% or less (more preferably 30 at% or less).
そして、前記原料流体組成物を前述の高速剪断速度の下で混合した後、実質的に共沈させることなく熱処理することによって、目的とする金属酸化物ナノ多孔体が得られる。また、前記原料流体組成物として金属塩溶液を用いた場合は、かかる熱処理によって原料流体組成物中の金属成分を酸化せしめて金属酸化物とすることによって、前述の本発明の金属酸化物ナノ多孔体を得ることができる。 And after mixing the said raw material fluid composition under the above-mentioned high-speed shear rate, it heat-processes without making it coprecipitate substantially, The target metal oxide nanoporous body is obtained. Further, when a metal salt solution is used as the raw material fluid composition, the metal oxide nanoporous material of the present invention described above is obtained by oxidizing the metal component in the raw material fluid composition by such heat treatment to form a metal oxide. You can get a body.
本発明においては、前記原料流体組成物を前述の混合の後に高速で熱処理することが好ましい。このような熱処理の具体的な方法は特に制限されないが、前記原料流体組成物を前述の混合の後に高速で乾燥し、さらに必要に応じて焼成する方法が好適に採用される。 In the present invention, the raw material fluid composition is preferably heat-treated at a high speed after the aforementioned mixing. Although the specific method of such heat treatment is not particularly limited, a method in which the raw material fluid composition is dried at a high speed after the above-mentioned mixing, and further fired as necessary is suitably employed.
本発明においては、前記原料流体組成物を前述の高速剪断速度の下で混合した後に前記熱処理するまでの時間は短い方が望ましく、６０分以内程度であることが好ましく、３０分以内程度であることがより好ましい。この時間が上記上限を超えると、高剪断攪拌の効果が低下して熱処理前や熱処理工程において金属酸化物が凝集し、付着性及び耐熱性が十分に向上した金属酸化物ナノ多孔体が得られにくくなる。 In the present invention, it is desirable that the time until the heat treatment after mixing the raw material fluid composition under the above-mentioned high shear rate is shorter, preferably within 60 minutes, preferably within 30 minutes. It is more preferable. When this time exceeds the above upper limit, the effect of high shear stirring is reduced, the metal oxide aggregates before heat treatment or in the heat treatment step, and a metal oxide nanoporous material with sufficiently improved adhesion and heat resistance is obtained. It becomes difficult.
また、後述する焼成工程が乾燥工程を兼ねていてもよいが、前記原料流体組成物を焼成する前に溶媒を除去して高速で乾燥せしめることが好ましく、その際における乾燥条件としては、６０〜１８０℃の温度（特に好ましくは１００〜１５０℃の温度）で１０分以内（特に好ましくは５分以内）に乾燥せしめるという条件がより好ましい。乾燥温度が上記下限未満では、高速乾燥が十分に達成されにくくなる傾向にあり、他方、上記上限を超えると、乾燥初期における乾燥速度が急激すぎることとなり、成膜速度より水分の気化速度が速すぎることから亀裂、ワレ等の原因となり、結果として付着性が大幅に低下する傾向にある。また、乾燥時間が上記上限を超えると、高剪断攪拌の効果が低下して乾燥工程において金属酸化物が凝集し、付着性及び耐熱性が十分に向上した金属酸化物ナノ多孔体が得られにくくなる傾向にある。なお、かかる高速乾燥工程において、原料流体組成物の含水率が２００質量％以下（特に好ましくは１００質量％以下）となるまで乾燥させることが好ましい。 Moreover, although the baking process mentioned later may serve as a drying process, it is preferable to remove a solvent and to dry at high speed before baking the said raw material fluid composition, As drying conditions in that case, 60- The condition of drying at a temperature of 180 ° C. (particularly preferably 100 to 150 ° C.) within 10 minutes (particularly preferably within 5 minutes) is more preferable. If the drying temperature is less than the above lower limit, high-speed drying tends to be difficult to achieve sufficiently. Since it is too much, it causes cracks, cracks and the like, and as a result, the adhesion tends to be greatly reduced. In addition, if the drying time exceeds the above upper limit, the effect of high shear stirring is reduced, the metal oxide aggregates in the drying step, and it is difficult to obtain a metal oxide nanoporous material with sufficiently improved adhesion and heat resistance. Tend to be. In this high-speed drying step, it is preferable to dry the raw material fluid composition until the water content becomes 200% by mass or less (particularly preferably 100% by mass or less).
さらに、焼成条件としては、酸化雰囲気（例えば、空気）中において２５０〜６００℃の温度（特に好ましくは３５０〜５００℃の温度）で２０〜７０分（特に好ましくは３０〜６０分）焼成するという条件がより好ましい。焼成温度が上記下限未満では、焼成が十分に達成されず、付着性及び耐熱性が十分に向上した金属酸化物ナノ多孔体が得られにくくなる傾向にあり、他方、上記上限を超えると、高温・酸化雰囲気によりシンタリング等の性能低下を伴い易くなる傾向にある。また、焼成時間が上記下限未満では、焼成が十分に達成されず、付着性及び耐熱性が十分に向上した金属酸化物ナノ多孔体が得られにくくなる傾向にあり、他方、上記上限を超えると、高剪断攪拌の効果が低下して焼成工程において金属酸化物が凝集し、付着性及び耐熱性が十分に向上した金属酸化物ナノ多孔体が得られにくくなる傾向にある。 Furthermore, as firing conditions, the firing is performed at a temperature of 250 to 600 ° C. (particularly preferably 350 to 500 ° C.) for 20 to 70 minutes (particularly preferably 30 to 60 minutes) in an oxidizing atmosphere (for example, air). Conditions are more preferred. When the firing temperature is less than the above lower limit, firing is not sufficiently achieved, and it tends to be difficult to obtain a metal oxide nanoporous material with sufficiently improved adhesion and heat resistance. -The oxidizing atmosphere tends to be accompanied by performance degradation such as sintering. Also, if the firing time is less than the above lower limit, firing is not sufficiently achieved, and it tends to be difficult to obtain a metal oxide nanoporous body with sufficiently improved adhesion and heat resistance, and on the other hand, when the upper limit is exceeded. The effect of high shear stirring is reduced, the metal oxide aggregates in the firing step, and it tends to be difficult to obtain a metal oxide nanoporous material having sufficiently improved adhesion and heat resistance.
なお、上記本発明の製造方法においては、前記本発明の金属酸化物ナノ多孔体として薄膜状のものや粉末状のものを好適に得ることができる。 In the production method of the present invention, a thin film or powder can be suitably obtained as the metal oxide nanoporous material of the present invention.
本発明の触媒担体における薄膜状の金属酸化物ナノ多孔体を得る場合、前記原料流体組成物を前記高速剪断速度の下で混合した後、実質的に共沈させることなく基材に塗布した後に熱処理する方法が好適に採用される。 In the case of obtaining a thin metal oxide nanoporous body in the catalyst support of the present invention, after mixing the raw material fluid composition under the high-speed shear rate, and after applying to the substrate without substantially co-precipitation A heat treatment method is preferably employed.
本発明の触媒担体において用いられる基材は特に制限されず、モノリス担体基材（ハニカムフィルタ、高密度ハニカム等）、フォームフィルタ基材、ペレット状基材、プレート状基材等が好適に採用される。また、このような基材の材質も特に制限されず、コージエライト、炭化ケイ素、ムライト等のセラミックスからなる基材や、クロム及びアルミニウムを含むステンレススチール等の金属からなる基材が好適に採用される。なお、金属からなる基材を用いる場合は、予め３００〜１０００℃、１〜１０時間程度の熱処理を施してその表面に酸化被膜を形成させておくと、付着性がより向上する傾向にあるため好ましい。 The substrate used in the catalyst carrier of the present invention is not particularly limited, and monolith carrier substrates (honeycomb filters, high-density honeycombs, etc.), foam filter substrates, pellet-shaped substrates, plate-shaped substrates and the like are suitably employed. The Further, the material of the base material is not particularly limited, and a base material made of a ceramic such as cordierite, silicon carbide, mullite, or a base material made of a metal such as stainless steel including chromium and aluminum is suitably employed. . In addition, when using the base material which consists of metals, when it heat-processes about 300-1000 degreeC for about 1 to 10 hours beforehand and forms the oxide film on the surface, it exists in the tendency for adhesiveness to improve more. preferable.
本発明において基材に塗布する原料流体組成物の量は特に制限されず、用いる基材や得られる触媒の用途等に応じて適宜調整されるが、基材体積１リットルに対して被覆を構成する金属酸化物の量が１０〜３００ｇ程度となる量が好ましい。 In the present invention, the amount of the raw material fluid composition applied to the base material is not particularly limited, and is appropriately adjusted according to the base material to be used and the use of the resulting catalyst. The amount of the metal oxide to be used is preferably about 10 to 300 g.
また、本発明において、前記原料流体組成物を基材に塗布する具体的な方法は特に制限されず、例えば、前記原料流体組成物に基材を浸漬する方法や、前記原料流体組成物をスプレー等により基材表面にコーティングする方法が好適に用いられる。 In the present invention, a specific method for applying the raw material fluid composition to the base material is not particularly limited. For example, a method of immersing the base material in the raw material fluid composition, or spraying the raw material fluid composition A method of coating the surface of the substrate by, for example, is preferably used.
また、所望の担持量になるまで前記原料流体組成物を基材に塗布する工程を繰り返してもよく、その場合は、前記原料流体組成物を基材に塗布して乾燥せしめた後に仮焼成することが好ましい。その際における仮焼成条件としては、酸化雰囲気（例えば、空気）中において２５０〜３００℃の温度で３０〜６０分仮焼成するという条件が特に好ましい。 Further, the step of applying the raw material fluid composition to the base material may be repeated until a desired loading amount is obtained. In that case, the raw material fluid composition is applied to the base material and dried, followed by temporary baking. It is preferable. As pre-baking conditions in that case, the conditions of pre-baking for 30 to 60 minutes at a temperature of 250 to 300 ° C. in an oxidizing atmosphere (for example, air) are particularly preferable.
また、粉末状の金属酸化物ナノ多孔体を得る場合、前記原料流体組成物を前記高速剪断速度の下で混合した後、実質的に共沈させることなく熱処理及び粉体化する方法が好適に採用される。このように前記原料流体組成物を粉体化する方法は特に制限されないが、前記原料流体組成物を乾燥及び必要に応じて焼成した後に粉砕して金属酸化物ナノ多孔体の粉体を得る方法が好適に用いられる。 In addition, when obtaining a powdered metal oxide nanoporous material, a method in which the raw material fluid composition is mixed at the high shear rate and then heat treated and powdered without substantial coprecipitation is preferably used. Adopted. The method for pulverizing the raw material fluid composition in this way is not particularly limited. However, the raw material fluid composition is dried and, if necessary, baked and then pulverized to obtain a metal oxide nanoporous powder. Are preferably used.
以上説明した本発明の金属酸化物ナノ多孔体は、前述のジルコニア及びセリアを特定量含有するジルコニア／セリア２成分系又はジルコニア、セリア及びアルミナを特定量含有するジルコニア／セリア／アルミナ３成分系により構成される複合金属酸化物であって、以下に説明する条件（Ｉ）を満たすものであることが好ましい。 The metal oxide nanoporous material of the present invention described above is obtained by the zirconia / ceria two-component system containing a specific amount of zirconia and ceria or the zirconia / ceria / alumina three-component system containing a specific amount of zirconia, ceria and alumina. It is preferable that the composite metal oxide is configured to satisfy the condition (I) described below.
すなわち、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第一の条件（Ｉ）は、前記ナノ多孔体に１０ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧２００ｋＶ、電子ビーム径１．０ｎｍの透過型電子顕微鏡を用いて被検試料の厚さが略一定とみなせる領域にある測定点においてエネルギー分散型Ｘ線分光法によりスペクトルを求め、得られたスペクトル中の各金属元素の蛍光Ｘ線ピークの積分強度を相対比に変換して求められる相対強度比Ｘの平均値Ｘｍと平均値Ｘｍのまわりの二次のモーメントν２とが、前記金属元素のすべてについて下記式（１）：
ν２／Ｘｍ ２≦０．０２ （１）
で表される条件を満たしていることである。前記式（１）において、Ｘｍは、下記式：
Ｘｍ＝（ΣＸ）／Ｎ
（式中のＮは測定点の数を示す。）
で表される相対強度比Ｘの平均値である。また、ν２は、下記式：
ν２＝｛Σ（Ｘ−Ｘｍ）２｝／Ｎ
で表される平均値Ｘｍのまわりの二次のモーメントである。さらに、ν２／Ｘｍ ２は、平均値Ｘｍの二乗で規格化した二次のモーメントである。
That is, the first condition (I) that is preferably satisfied by the metal oxide nanoporous material of the present invention is that the acceleration voltage is 200 kV for all metal elements of the metal oxide contained in the nanoporous material at 10 at% or more, Using a transmission electron microscope having an electron beam diameter of 1.0 nm, a spectrum is obtained by energy dispersive X-ray spectroscopy at a measurement point in a region where the thickness of the test sample can be regarded as substantially constant, and each spectrum in the obtained spectrum is obtained. The average value X m of the relative intensity ratio X obtained by converting the integrated intensity of the fluorescent X-ray peak of the metal element into a relative ratio and the second moment ν 2 around the average value X m are all of the metal elements. About the following formula (1):
ν 2 / X m 2 ≦ 0.02 (1)
The condition represented by is satisfied. In the above formula (1), Xm represents the following formula:
X m = (ΣX) / N
(N in the formula indicates the number of measurement points.)
Is the average value of the relative intensity ratio X represented by Also, ν 2 is the following formula:
ν 2 = {Σ (X−X m ) 2 } / N
In a second moment around the mean value X m represented. Furthermore, ν 2 / X m 2 is a second moment normalized by the square of the average value X m .
なお、このような測定の具体的な方法は特に限定されないが、例えば以下に示す測定方法にしたがって実施することが好ましい。 In addition, although the specific method of such a measurement is not specifically limited, For example, it is preferable to implement according to the measuring method shown below.
＜試料の作製＞
金属酸化物ナノ多孔体を少量採取し、容器中に貯めた５〜１０ｍｌ程度の分散媒（例えばエタノール）に混合する。得られた混合物を超音波洗浄機の水槽に入れ、数分間超音波にて撹拌した後、直ちに容器を超音波洗浄機から取り出して被検試料の分散液を、「マイクログリッド」と呼ばれる３ｍｍφ程度の銅箔のメッシュの上に多孔質の有機膜を貼った透過型電子顕微鏡専用の試料台上に１〜２滴、滴下する。そして、分散媒を完全に蒸発させた後に透過型電子顕微鏡による観察を行う。
<Preparation of sample>
A small amount of the metal oxide nanoporous material is collected and mixed with about 5 to 10 ml of a dispersion medium (for example, ethanol) stored in a container. The obtained mixture is put in a water tank of an ultrasonic cleaning machine, stirred for several minutes with ultrasonic waves, and immediately the container is taken out of the ultrasonic cleaning machine, and the dispersion of the test sample is about 3 mmφ called “microgrid”. One or two drops are dropped on a sample stage dedicated to a transmission electron microscope in which a porous organic film is pasted on a copper foil mesh. Then, after the dispersion medium is completely evaporated, observation with a transmission electron microscope is performed.
＜透過型電子顕微鏡観察＞
観察には、電界放射型電子銃（ＦＥＧ）を有する加速電圧２００ｋＶの透過型電子顕微鏡（ＴＥＭ）を用いる。ＴＥＭには、走査型透過電子顕微鏡（ＳＴＥＭ）観察モード及びエネルギー分散型Ｘ線分光（ＥＤＸ）用検出器が装備されていることが測定上必要な条件である。上記の被検試料を滴下したマイクログリッドをＴＥＭの試料室に挿入し、マイクログリッドの有機膜の孔の上にはみ出ている試料（すなわち試料が有機膜と重なっていない部分）を観察及び元素分析の対象とする。その際、被検試料の厚さの比較的薄い部分を選び出し、その部分にＳＴＥＭ観察モードで１ｎｍφに絞った電子線を３０秒照射し、試料から放出される蛍光Ｘ線をＥＤＸ検出器を用いて検出する。そして、試料の厚さに関し、ＥＤＸ検出器で得られる全Ｘ線の総カウント数を基準とし、１万カウントから６万カウントの間になる部分を測定に適正な領域、すなわち被検試料の厚さが略一定とみなせる領域と規定する。
<Transmission electron microscope observation>
For observation, a transmission electron microscope (TEM) having an accelerating voltage of 200 kV having a field emission electron gun (FEG) is used. The TEM is equipped with a scanning transmission electron microscope (STEM) observation mode and an energy dispersive X-ray spectroscopy (EDX) detector. Insert the microgrid onto which the above test sample is dropped into the TEM sample chamber, and observe and analyze the sample protruding from the hole of the organic film of the microgrid (that is, the part where the sample does not overlap the organic film) The target of. At that time, a comparatively thin portion of the sample to be tested is selected, and the portion is irradiated with an electron beam focused to 1 nmφ in the STEM observation mode for 30 seconds, and the fluorescent X-ray emitted from the sample is used with an EDX detector. To detect. Then, with respect to the thickness of the sample, based on the total count number of all X-rays obtained by the EDX detector, a portion that is between 10,000 counts and 60,000 counts is suitable for measurement, that is, the thickness of the test sample. It is defined as an area where the length can be regarded as substantially constant.
＜測定部位の良否の判定＞
測定部位がマイクログリッドの有機膜を支えている銅箔に近く、試料から放出される蛍光Ｘ線の一部がこの銅箔に当たって良好な元素分析が行えない場所がある。このような場所から得られるＥＤＸ検出結果の特徴としては、（１）全体的にカウント数が低い、（２）特に酸素の蛍光Ｘ線等の低エネルギー領域におけるカウント数が低い、（３）それに比べて銅のカウント数は高い、等の特徴がある。図１にこのような良好な元素分析が行えない場所の一例の透過型電子顕微鏡写真（図中、００６〜０１０は測定点を示す）を、図２にＥＤＸスペクトルの不良な測定結果の一例を示す。このような測定場所から得られた測定結果は全点考察の対象からはずし、別の有機膜の孔における被検試料を新たな測定対象として測定を続ける。例えば、後述する実施例においては、得られるＥＤＸスペクトルにおける（酸素の総カウント数）／（Ｃｕの総カウント数）の比がすべての測定点で２未満となる場所から得られた測定結果は計算の対象から除外し、ＥＤＸスペクトルにおける（酸素の総カウント数）／（Ｃｕの総カウント数）の比が２以上となる場所から得られた測定結果に基づいて後述の計算をする。図３に良好な元素分析が行えた場所の一例の透過型電子顕微鏡写真（図中、００１〜００５は測定点を示す）を、図４にＥＤＸスペクトルの良好な測定結果の一例を示す。
<Determining the quality of the measurement site>
There is a place where the measurement site is close to the copper foil supporting the organic film of the microgrid, and a part of the fluorescent X-rays emitted from the sample hits the copper foil and good elemental analysis cannot be performed. The characteristics of the EDX detection result obtained from such a place are as follows: (1) The overall count number is low, (2) The count number is low particularly in low energy regions such as fluorescent X-rays of oxygen, (3) Compared to this, the copper count is high. FIG. 1 shows a transmission electron micrograph of an example of such a place where good elemental analysis cannot be performed (in the figure, 006 to 010 indicate measurement points), and FIG. 2 shows an example of a poor measurement result of the EDX spectrum. Show. The measurement result obtained from such a measurement place is excluded from the object of all points consideration, and the measurement is continued with the test sample in the hole of another organic film as a new measurement object. For example, in the examples described later, the measurement results obtained from the locations where the ratio of (total oxygen count) / (total Cu count) in the obtained EDX spectrum is less than 2 at all measurement points are calculated. The calculation described later is performed based on the measurement result obtained from the location where the ratio of (total oxygen count) / (total Cu count) in the EDX spectrum is 2 or more. FIG. 3 shows a transmission electron micrograph of an example of a place where good elemental analysis can be performed (in the figure, 001 to 005 indicate measurement points), and FIG. 4 shows an example of a good measurement result of the EDX spectrum.
＜測定結果に基づく計算＞
本発明においては、前記条件の判定をする際に、ＥＤＸスペクトルのデータを無加工で使用する。すなわち、何らかの変換式を用いて元素の重量比等に変換した数値ではなく、蛍光Ｘ線のカウント数そのものを計算の基礎とする。先ず、ＥＤＸスペクトルより試料を構成する主な金属元素（試料に１０ａｔ％以上含有されるすべての金属酸化物の金属元素）である例えばＡｌ、Ｚｒ、Ｃｅの蛍光Ｘ線ピークの中から、（１）なるべくカウント数の多いもの、（２）他のピークとの重なりが無視できるほど小さいもの、の２点を基準にして各金属元素について一つのピークを選択する。そして、選択された各ピークをすべて覆えるだけの必要且つ十分なエネルギー幅（０．２〜０．３ｋｅＶ程度）を定め、その範囲にある蛍光Ｘ線のカウント数をすべて足し合わせ、これをその金属元素の蛍光Ｘ線ピークの積分強度として求め、その結果に基づいて前述の相対強度比Ｘ、その平均値Ｘｍ、平均値Ｘｍのまわりの二次のモーメントν２、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を順次算出し、前記式（１）で表される条件を満たしているか否かを判定する。
<Calculation based on measurement results>
In the present invention, when the condition is determined, EDX spectrum data is used without processing. That is, the calculation is based on the fluorescent X-ray count itself, not the numerical value converted into the element weight ratio or the like using any conversion formula. First, from the fluorescent X-ray peaks of, for example, Al, Zr, and Ce, which are main metal elements constituting the sample (metal elements of all metal oxides contained in the sample by 10 at% or more) from the EDX spectrum, (1 One peak is selected for each metal element based on two points: as many counts as possible (2) as few as possible so that the overlap with other peaks is negligible. Then, a necessary and sufficient energy width (about 0.2 to 0.3 keV) that covers all the selected peaks is determined, and all counts of fluorescent X-rays in the range are added, and this is calculated as the integral intensity of the fluorescent X-ray peak of the metal element, so that on the basis of the aforementioned relative intensity ratio X, its mean value X m, average second moment [nu 2 around X m, the average value X m Secondary moments ν 2 / X m 2 normalized by the square are sequentially calculated, and it is determined whether or not the condition expressed by the above formula (1) is satisfied.
本発明の金属酸化物ナノ多孔体が前記式（１）で表される条件を満たすということは、そのナノ多孔体を構成する主要な金属酸化物がナノ細孔を構成する壁体中で極めて均一に分散していることを示している。このような極めて高水準の成分均一性は、金属酸化物のコロイド溶液や金属塩の溶液をそのまま用いて得られる金属酸化物では決して得られるものではなく、本発明にかかる製造方法によってはじめて達成されたものである。そして、前記式（１）で表される条件を満たす金属酸化物ナノ多孔体においては、驚くべきことに、その条件を満たさない従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が飛躍的に向上している。 The fact that the metal oxide nanoporous material of the present invention satisfies the condition represented by the above formula (1) means that the main metal oxide constituting the nanoporous material is extremely in the wall constituting the nanopore. It shows that it is uniformly dispersed. Such an extremely high level of component uniformity is never obtained with a metal oxide obtained by using a metal oxide colloidal solution or a metal salt solution as it is, and is achieved only by the production method according to the present invention. It is a thing. And in the metal oxide nanoporous material that satisfies the condition represented by the formula (1), surprisingly, the adhesion to various substrates and the conventional metal oxide porous material that does not satisfy the condition and Heat resistance has improved dramatically.
また、本発明の金属酸化物ナノ多孔体は、以下に説明する条件（II）（好ましくは（II’））、（III）、（IV）、（V）のうちの少なくとも一つを満たすものであることがより好ましく、特に原料流体組成物としてコロイド溶液を用いて得た金属酸化物ナノ多孔体は条件（II）（好ましくは（II’））、（III）、（IV）のうちの少なくとも一つを満たすことが好ましく、他方、原料流体組成物として金属塩溶液を用いて得た金属酸化物ナノ多孔体は条件（V）を満たすことが好ましい。 Further, the metal oxide nanoporous material of the present invention satisfies at least one of the conditions (II) (preferably (II ′)), (III), (IV), and (V) described below. In particular, the metal oxide nanoporous material obtained by using a colloidal solution as a raw material fluid composition is preferably one of the conditions (II) (preferably (II ′)), (III), (IV) It is preferable to satisfy at least one. On the other hand, the metal oxide nanoporous material obtained by using a metal salt solution as the raw material fluid composition preferably satisfies the condition (V).
本発明の金属酸化物ナノ多孔体は、以下に説明する条件（II）を満たすものであることが好ましい。 The metal oxide nanoporous material of the present invention preferably satisfies the condition (II) described below.
すなわち、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第二の条件（II）は、前記ナノ多孔体に１０ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザーを用いて０．５ｍｍ以上の範囲を任意に線分析して求めた下記式（２）：
Ｋ値（％）＝（多孔体から検出されたＸ線強度）／（純物質から得られるＸ線強度）
で表されるＫ値が、前記金属元素のすべてについて、全測定点のうちの６５％以上（特に好ましくは７５％以上）の測定点において下記式（３）：
That is, the second condition (II) that is preferably satisfied by the metal oxide nanoporous material of the present invention is that an acceleration voltage of 15 kV for all metal oxide metal elements contained in the nanoporous material is 10 at% or more, The following formula (2) obtained by arbitrarily analyzing a range of 0.5 mm or more using an X-ray microanalyzer having an electron beam diameter of 1 μm:
K value (%) = (X-ray intensity detected from porous material) / (X-ray intensity obtained from pure substance)
The K value represented by the following formula (3) at the measurement points of 65% or more (particularly preferably 75% or more) of all the measurement points for all the metal elements:
で表される条件を満たしていることである。 The condition represented by is satisfied.
また、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第二’の条件（II’）は、前記ナノ多孔体に５ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザーを用いて０．５ｍｍ以上の範囲を任意に線分析して求めた前記式（２）で表されるＫ値が、前記金属元素のすべてについて、全測定点のうちの４０％以上の測定点において前記式（３）で表される条件を満たしていることである。 In addition, the second condition (II ′) that is preferably satisfied by the metal oxide nanoporous material of the present invention is that the acceleration voltage is applied to the metal elements of all metal oxides contained in the nanoporous material by 5 at% or more. The K value represented by the formula (2) obtained by arbitrarily analyzing the range of 0.5 mm or more using an X-ray microanalyzer with an electron beam diameter of 15 μV and an electron beam diameter of 1 μm is obtained for all the metal elements. That is, the condition represented by the above formula (3) is satisfied at 40% or more of the measurement points.
前記式（３）において、Ｋは各測定点におけるＫ値（％）、Ｋｍは全測定点におけるＫ値の平均値をそれぞれ示す。また、実際に線分析した測定点のうち、前記多孔体に形成されている亀裂に相当する部分については測定点から除外して、前記のＫ値を求める。なお、このような亀裂の認識方法としては、Ｘ線マイクロアナライザーの測定結果において基板の成分が所定量以上検出された部分を亀裂と認識する方法、或いは、光学又は電子顕微鏡による観察によって亀裂を認識する方法が好適に採用される。また、ここで用いられるＸ線マイクロアナライザーとしては、通常の波長分散型の機種であればよく、特に限定されるものではない。 In the formula (3), K K value (%) at each measuring point, K m denotes a mean value of the K values at all the measurement points. Further, among the measurement points actually subjected to the line analysis, the portion corresponding to the crack formed in the porous body is excluded from the measurement points, and the K value is obtained. As a method for recognizing such a crack, a method of recognizing a portion where a predetermined amount or more of the substrate component is detected as a crack in the measurement result of the X-ray microanalyzer, or recognizing the crack by observation with an optical or electron microscope. This method is preferably employed. The X-ray microanalyzer used here is not particularly limited as long as it is a normal wavelength dispersion type model.
本発明の金属酸化物ナノ多孔体が上記の条件（II）（好ましくは（II’））を満たすということは、それを構成する主要な金属酸化物がナノ多孔体中で極めて均一に分散していることを示している。このような極めて高水準の成分均一性は、金属酸化物のコロイド溶液や金属塩の溶液をそのまま用いて得られる金属酸化物では決して得られるものではなく、本発明にかかる製造方法によってはじめて達成されたものである。そして、上記の条件（II）（好ましくは（II’））を満たす金属酸化物ナノ多孔体においては、驚くべきことに、条件（II）を満たさない従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が飛躍的に向上している。 The fact that the metal oxide nanoporous material of the present invention satisfies the above condition (II) (preferably (II ′)) means that the main metal oxide constituting it is dispersed extremely uniformly in the nanoporous material. It shows that. Such an extremely high level of component uniformity is never obtained with a metal oxide obtained by using a metal oxide colloidal solution or a metal salt solution as it is, and is achieved only by the production method according to the present invention. It is a thing. And surprisingly, in the metal oxide nanoporous material that satisfies the above condition (II) (preferably (II ′)), various kinds of metal oxide nanoporous materials that do not satisfy the condition (II) can be used. Adhesion to the base material and heat resistance are dramatically improved.
本発明の金属酸化物ナノ多孔体は、以下に説明する条件（III）を満たすものであることが好ましい。 The metal oxide nanoporous material of the present invention preferably satisfies the condition (III) described below.
すなわち、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第三の条件（III）は、走査型プローブ顕微鏡（ＳＰＭ）にて５ｎｍの曲率半径を有するチップを用いて、３ｎｍ以上４ｎｍ未満の間隔で前記ナノ多孔体の表面の高さ像をタッピングモードで任意に計測し、総計で２μｍ以上の走査距離Ｌの関数として求めた高さ像Ｈ（Ｌ）が、全測定点のうちの８０％以上（特に好ましくは９０％以上）の測定点において下記式（４）：
Ｈ（Ｌ）≦２０ｎｍ （４）
［式（４）中、Ｈ（Ｌ）は各測定点（走査距離＝Ｌ）における高さ像（ｎｍ）を示す。但し、全測定点における高さ像Ｈの平均値を零とする。］
で表される条件を満たしており、且つ、下記式（５）及び（６）：
That is, the third condition (III) that the metal oxide nanoporous material of the present invention preferably satisfies is 3 nm or more and less than 4 nm using a tip having a curvature radius of 5 nm with a scanning probe microscope (SPM). The height image of the surface of the nanoporous material is arbitrarily measured in the tapping mode at intervals, and the height image H (L) obtained as a function of the scanning distance L of 2 μm or more in total is 80% of all measurement points. % (Especially preferably 90% or more) at the measurement points of the following formula (4):
H (L) ≦ 20nm (4)
[In Expression (4), H (L) represents a height image (nm) at each measurement point (scanning distance = L). However, the average value of the height image H at all measurement points is set to zero. ]
And the following formulas (5) and (6):
［式（５）及び（６）中、Ｈ（Ｌ）は走査距離＝Ｌの測定点における高さ像（ｎｍ）、Ｈ（Ｌ＋ΔＬ）は走査距離＝Ｌ＋ΔＬの測定点における高さ像（ｎｍ）、ΔＬは測定点の間隔（ｎｍ）、Ｈ’（Ｌ）は高さ像Ｈ（Ｌ）の一次微係数、Ｈ’（Ｌ＋ΔＬ）は高さ像Ｈ（Ｌ＋ΔＬ）の一次微係数、Ｈ”（Ｌ）は高さ像Ｈ（Ｌ）の二次微係数をそれぞれ示す。但し、ΔＬは測定点間の直線補間により４ｎｍとする。］
により求めた二次微係数Ｈ”（Ｌ）が、全測定点のうちの６０％以下（特に好ましくは５５％以下）の測定点において下記式（７）：
−０．０５ｎｍ−１≦Ｈ”（Ｌ）≦０．０５ｎｍ−１ （７）
で表される条件を満たしていることである。なお、上記の二次微係数Ｈ”（Ｌ）を求める際に、平滑化の処理は一切行わない。
[In formulas (5) and (6), H (L) is the height image (nm) at the measurement point where the scanning distance = L, and H (L + ΔL) is the height image (nm) at the measurement point where the scanning distance = L + ΔL. , ΔL is the measurement point interval (nm), H ′ (L) is the first derivative of the height image H (L), H ′ (L + ΔL) is the first derivative of the height image H (L + ΔL), and H ″ ( L) represents the second derivative of the height image H (L), where ΔL is 4 nm by linear interpolation between measurement points.]
The following second formula (7) is obtained at the measurement points where the second derivative H ″ (L) obtained by the equation (1) is 60% or less (particularly preferably 55% or less) of all the measurement points:
−0.05 nm −1 ≦ H ″ (L) ≦ 0.05 nm −1 (7)
The condition represented by is satisfied. Note that no smoothing process is performed when obtaining the second derivative H ″ (L).
本発明の金属酸化物ナノ多孔体が上記の条件（III）の前段を満たすということは、高さの分布が小さい部分に偏っていて表面が細かい凹凸状態であることを示しており、他方、上記の条件（III）の後段を満たすということは、二次の微分係数に比較的大きな値が含まれていて表面の凹面や凸面そのものが滑らかではなく、表面凹凸の上に更に非常に細かい小突起が多い状態であることを示している。このような特殊な表面形状は、金属酸化物のコロイド溶液や金属酸化物の溶液をそのまま用いて得られる金属酸化物では決して得られるものではなく、本発明にかかる製造方法によってはじめて達成されたものである。そして、上記の条件（III）を満たす金属酸化物ナノ多孔体においては、驚くべきことに、条件（III）を満たさない従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が向上している。 The fact that the metal oxide nanoporous material of the present invention satisfies the preceding stage of the above condition (III) indicates that the height distribution is biased toward a small portion and the surface is in a fine uneven state, Satisfying the latter stage of the above condition (III) means that the secondary differential coefficient contains a relatively large value and the surface concave and convex surfaces themselves are not smooth, and the surface irregularities are much smaller. It shows that there are many protrusions. Such a special surface shape is never obtained with a metal oxide obtained by using a metal oxide colloidal solution or a metal oxide solution as it is, and has been achieved for the first time by the production method according to the present invention. It is. And surprisingly, in the metal oxide nanoporous material satisfying the above condition (III), the adhesion and heat resistance to various substrates as compared with the conventional metal oxide porous material not satisfying the condition (III). Has improved.
本発明の金属酸化物ナノ多孔体は、以下に説明する条件(IV)を満たすものであることが好ましい。 The metal oxide nanoporous material of the present invention preferably satisfies the condition (IV) described below.
すなわち、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第四の条件(IV)は、前記ナノ多孔体の断面の電子顕微鏡写真において、前記ナノ多孔体の上に任意に総計で４００μｍ以上の測定直線を描いた際に、前記測定直線が前記ナノ多孔体に形成されている空隙部（ナノ細孔は除く）と交差している部分の長さの比率が、前記測定直線の全長の１０％以下（特に好ましくは５％以下）であるという条件を満たしていることである。 That is, the fourth condition (IV) preferably satisfied by the metal oxide nanoporous material of the present invention is that, in the electron micrograph of the cross section of the nanoporous material, a total of 400 μm or more arbitrarily on the nanoporous material. When the measurement straight line is drawn, the ratio of the length of the portion where the measurement straight line intersects the void portion (excluding the nanopore) formed in the nanoporous body is the total length of the measurement straight line. The condition of 10% or less (particularly preferably 5% or less) is satisfied.
本発明の金属酸化物ナノ多孔体が上記の条件(IV)を満たすということは、そのナノ多孔体を構成する金属酸化物において適度な連続性が確保されており、ナノ多孔体中に空隙が少ないことを示している。このように適度な連続性が確保されていて空隙が少ない断面性状を有する金属酸化物ナノ多孔体は、従来のスラリーを用いて得られる金属酸化物では決して得られるものではなく、本発明にかかる製造方法によってはじめて達成されたものである。そして、上記の条件(IV)を満たす金属酸化物ナノ多孔体においては、驚くべきことに、条件(IV)を満たさない従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が向上している。 The fact that the metal oxide nanoporous material of the present invention satisfies the above condition (IV) means that appropriate continuity is ensured in the metal oxide constituting the nanoporous material, and there are voids in the nanoporous material. It shows that there are few. Thus, the metal oxide nanoporous body having a cross-sectional property in which moderate continuity is ensured and the number of voids is small is never obtained with a metal oxide obtained by using a conventional slurry, and is according to the present invention. This was achieved for the first time by the manufacturing method. And in the metal oxide nanoporous material satisfying the above condition (IV), surprisingly, the adhesion and heat resistance to various substrates as compared with the conventional metal oxide porous material not satisfying the condition (IV). Has improved.
本発明の金属酸化物ナノ多孔体は、以下に説明する条件(Ｖ)を満たすものであることが好ましい。 The metal oxide nanoporous material of the present invention preferably satisfies the condition (V) described below.
すなわち、本発明の金属酸化物ナノ多孔体が満たすことが好ましい第五の条件(Ｖ)は、前記ナノ多孔体に１０ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧２００ｋＶ、電子ビーム径１．０ｎｍの透過型電子顕微鏡を用いて任意に１０以上の測定点においてエネルギー分散型Ｘ線分光法によりスペクトルを求め、得られたスペクトル中の各金属元素の蛍光Ｘ線ピークの積分強度を相対比に変換して求められる相対強度比Ｘの平均値Ｘｍと平均値Ｘｍのまわりの二次のモーメントν２とが、前記金属元素のすべてについて下記式（８）：
ν２／Ｘｍ ２≦０．１ （８）
で表される条件を満たしていることである。前記式（８）において、Ｘｍは、下記式：
Ｘｍ＝（ΣＸ）／Ｎ
（式中のＮは測定点の数を示す。）
で表される相対強度比Ｘの平均値である。また、ν２は、下記式：
ν２＝｛Σ（Ｘ−Ｘｍ）２｝／Ｎ
で表される平均値Ｘｍのまわりの二次のモーメントである。さらに、ν２／Ｘｍ ２は、平均値Ｘｍの二乗で規格化した二次のモーメントである。
That is, the fifth condition (V) that is preferably satisfied by the metal oxide nanoporous material of the present invention is that the acceleration voltage is 200 kV for all metal elements of the metal oxide contained in the nanoporous material by 10 at% or more, Using a transmission electron microscope having an electron beam diameter of 1.0 nm, a spectrum is arbitrarily obtained by energy dispersive X-ray spectroscopy at 10 or more measurement points, and integration of fluorescent X-ray peaks of each metal element in the obtained spectrum is performed. The average value X m of the relative intensity ratio X obtained by converting the intensity into the relative ratio and the second moment ν 2 around the average value X m are expressed by the following formula (8):
ν 2 / X m 2 ≦ 0.1 (8)
The condition represented by is satisfied. In the above formula (8), X m represents the following formula:
X m = (ΣX) / N
(N in the formula indicates the number of measurement points.)
Is the average value of the relative intensity ratio X represented by Also, ν 2 is the following formula:
ν 2 = {Σ (X−X m ) 2 } / N
In a second moment around the mean value X m represented. Furthermore, ν 2 / X m 2 is a second moment normalized by the square of the average value X m .
なお、この条件(Ｖ)の判定方法の詳細（試料の作製、透過型電子顕微鏡観察、測定部位の良否の判定、測定結果に基づく計算）は、前記条件(I)の判定方法とほとんど同様であるが、条件(I)の判定方法のように被検試料の厚さが略一定とみなせる領域にある測定点についての測定値のみを用いる必要はなく、任意の１０以上の測定点であればよい。したがって、透過型電子顕微鏡観察の際に、被検試料の厚さに関し、ＥＤＸ検出器で得られる全Ｘ線の総カウント数を基準とし、１万カウントから１５万カウントの間になる部分を測定に適正な領域として採用することができる。 The details of the determination method for the condition (V) (sample preparation, observation with a transmission electron microscope, determination of the quality of the measurement site, calculation based on the measurement result) are almost the same as the determination method for the condition (I). However, it is not necessary to use only the measurement values for the measurement points in the region in which the thickness of the test sample can be regarded as being substantially constant as in the determination method of the condition (I), and any arbitrary measurement point is 10 or more. Good. Therefore, when observing with a transmission electron microscope, the thickness of the test sample is measured with respect to the total count number of all X-rays obtained by the EDX detector as a reference between 10,000 counts and 150,000 counts. It can be adopted as an appropriate area.
本発明の金属酸化物ナノ多孔体が上記の条件(Ｖ)を満たすということは、そのナノ多孔体を構成する主要な金属酸化物がナノ多孔体中で極めて均一に分散していることを示している。このような極めて高水準の成分均一性は、金属酸化物のコロイド溶液や金属塩の溶液をそのまま用いて得られる金属酸化物では決して得られるものではなく、本発明にかかる製造方法によってはじめて達成されたものである。そして、前記の条件(Ｖ)を満たす金属酸化物ナノ多孔体においては、驚くべきことに、その条件を満たさない従来の金属酸化物多孔体に比べて各種基材に対する付着性及び耐熱性が向上している。 The fact that the metal oxide nanoporous material of the present invention satisfies the above condition (V) indicates that the main metal oxides constituting the nanoporous material are very uniformly dispersed in the nanoporous material. ing. Such an extremely high level of component uniformity is never obtained with a metal oxide obtained by using a metal oxide colloidal solution or a metal salt solution as it is, and is achieved only by the production method according to the present invention. It is a thing. And surprisingly, in the metal oxide nanoporous material satisfying the condition (V), the adhesion and heat resistance to various substrates are improved as compared with the conventional metal oxide porous material not satisfying the condition. is doing.
本発明にかかる金属酸化物ナノ多孔体は、上記条件(Ｉ)〜(Ｖ)のうちの１つの条件を満たしていることが好ましく、また条件(Ｉ)〜(Ｖ)のうちの２つ以上の条件を満たしていることがより好ましい。複数の条件を満たすことにより、そのナノ多孔体を構成する主要な金属酸化物がナノ多孔体中（ナノ細孔を構成する壁体中）で極めて均一に分散している。それによって各種基材に対する金属酸化物ナノ多孔体の付着性及び耐熱性を相乗的により向上させることができる。 The metal oxide nanoporous material according to the present invention preferably satisfies one of the above conditions (I) to (V), and two or more of the conditions (I) to (V). It is more preferable that the above condition is satisfied. By satisfying a plurality of conditions, the main metal oxide constituting the nanoporous body is dispersed extremely uniformly in the nanoporous body (in the wall constituting the nanopore). Thereby, the adhesion and heat resistance of the metal oxide nanoporous material to various substrates can be improved synergistically.
次に、本発明の水素生成反応用触媒について説明する。すなわち、本発明の水素生成反応用触媒は、前記本発明の触媒担体と、前記触媒担体の表面に担持される貴金属を備えることを特徴とするものである。 Next, the hydrogen production reaction catalyst of the present invention will be described. That is, the hydrogen production reaction catalyst of the present invention comprises the catalyst support of the present invention and a noble metal supported on the surface of the catalyst support.
本発明の水素生成反応用触媒において前記本発明の触媒担体の表面に担持される貴金属としては、特に制限されず、白金、ロジウム、パラジウム、オスミウム、イリジウム、金等が挙げられ、中でも白金、ロジウム、パラジウムが好ましい。また、このような貴金属の担持量は特に制限されず、得られる触媒の用途等に応じて適宜調整されるが、触媒担体を構成する前記金属酸化物１００質量部に対して０．１〜１０質量部程度となる量が一般的である。 The noble metal supported on the surface of the catalyst carrier of the present invention in the hydrogen production reaction catalyst of the present invention is not particularly limited, and examples thereof include platinum, rhodium, palladium, osmium, iridium, gold, etc. Among them, platinum, rhodium Palladium is preferred. In addition, the amount of such noble metal supported is not particularly limited and is appropriately adjusted according to the use of the obtained catalyst and the like, but is 0.1 to 10 with respect to 100 parts by mass of the metal oxide constituting the catalyst carrier. An amount of about part by mass is common.
また、このような貴金属を担持させる具体的な方法は特に制限されないが、例えば、貴金属の塩（硝酸塩、塩化物、酢酸塩等）又は貴金属の錯体を水、アルコール等の溶媒に溶解した溶液に前記本発明の触媒担体を浸漬し、溶媒を除去した後に焼成するといった方法が好適に用いられる。なお、前記貴金属を担持させる工程において溶媒を除去する際における乾燥条件としては３０〜１５０℃で１０分以内程度が好ましく、また、焼成条件としては、酸化雰囲気（例えば、空気）中において２５０〜３００℃で３０〜６０分程度が好ましい。また、所望の担持量になるまでこのような貴金属担持工程を繰り返してもよい。 The specific method for supporting such a noble metal is not particularly limited. For example, a noble metal salt (nitrate, chloride, acetate, etc.) or a noble metal complex dissolved in a solvent such as water or alcohol is used. A method of immersing the catalyst carrier of the present invention, removing the solvent, and calcining is preferably used. The drying condition for removing the solvent in the step of supporting the noble metal is preferably within 30 minutes at 30 to 150 ° C. The firing condition is 250 to 300 in an oxidizing atmosphere (for example, air). About 30 to 60 minutes are preferable at ° C. Moreover, you may repeat such a noble metal carrying | support process until it becomes a desired carrying amount.
以下、実施例及び比較例に基づいて本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。 EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.
なお、ホモジナイザとしては、特殊機化工業（株）製のＴ．Ｋ．ロボミックス（攪拌部はＴ．Ｋ．ホモミクサーＭＡＲＫII ２．５型）を用いた。 As a homogenizer, T.M. manufactured by Tokushu Kika Kogyo Co., Ltd. was used. K. ROBOMIX (stirring part: TK homomixer MARK II 2.5 type) was used.
また、アルミナ（Ａｌ２Ｏ３）コロイド、Ａｌ溶液、Ｚｒ溶液、ジルコニア（ＺｒＯ２）粉末、Ｃｅ溶液、Ｒｈ溶液としては、それぞれ以下のものを用いた。
Ａｌ２Ｏ３コロイド…平均粒径：５〜２０ｎｍ、針状粒子、硝酸水溶液（固形分濃度：２５質量％）、
Ａｌ溶液…硝酸アルミニウム水溶液（固形分濃度：５．４４質量％）、
Ｚｒ溶液…オキシ硝酸ジルコニウム水溶液（固形分濃度：１８質量％）、
ＺｒＯ２粉末…平均粒径：１μｍ、
Ｃｅ溶液…硝酸セリウム水溶液（固形分濃度：２８質量％）、
Ｒｈ溶液…硝酸ロジウム水溶液（固形分濃度：３質量％）。
Further, alumina (Al 2 O 3) colloid, Al solution, Zr solution, zirconia (ZrO 2) powder, Ce solution, as the Rh solution, the following were used, respectively.
Al 2 O 3 colloid: average particle diameter: 5 to 20 nm, acicular particles, nitric acid aqueous solution (solid content concentration: 25% by mass),
Al solution: aluminum nitrate aqueous solution (solid content concentration: 5.44% by mass),
Zr solution: zirconium oxynitrate aqueous solution (solid content concentration: 18% by mass),
ZrO 2 powder: average particle diameter: 1 μm,
Ce solution: cerium nitrate aqueous solution (solid content concentration: 28% by mass),
Rh solution: aqueous rhodium nitrate solution (solid content concentration: 3% by mass).
さらに、成分均一性、表面形状及び耐熱性を評価するための基材としては、クロム及びアルミニウムを含むステンレススチールからなる金属プレート（Ｆｅ−２０Ｃｒ−５Ａｌ、５０ｍｍ×５０ｍｍ×０．３ｍｍ）を用い、予め１０００℃で１時間の熱処理を施してその表面に酸化被膜を形成せしめて用いた。また、断面性状を評価するための基材としては、４００メッシュのハニカム形状を有するコージエライト基板及び１５００メッシュのハニカム形状を有するコージエライト基板を用いた。さらに、改質耐久性を評価するための基材としては、１２００cell／inch２の金属製高密度ハニカム（Ｆｅ−２０Ｃｒ−５Ａｌ）を用いた。また、付着性を評価するための基材としては、上記の金属プレートに加えて、コージエライトプレート（５０ｍｍ×５０ｍｍ×１ｍｍ）及びＳｉＣプレート（５０ｍｍ×５０ｍｍ×１ｍｍ）を用いた。 Furthermore, as a base material for evaluating component uniformity, surface shape and heat resistance, a metal plate made of stainless steel containing chromium and aluminum (Fe-20Cr-5Al, 50 mm × 50 mm × 0.3 mm) is used. A heat treatment was performed at 1000 ° C. for 1 hour in advance to form an oxide film on the surface. In addition, a cordierite substrate having a 400-mesh honeycomb shape and a cordierite substrate having a 1500-mesh honeycomb shape were used as base materials for evaluating the cross-sectional properties. Furthermore, a 1200 cell / inch 2 metal high-density honeycomb (Fe-20Cr-5Al) was used as a base material for evaluating the modification durability. In addition to the above metal plate, a cordierite plate (50 mm × 50 mm × 1 mm) and a SiC plate (50 mm × 50 mm × 1 mm) were used as the base material for evaluating adhesion.
（実施例１）
得られる被覆におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝３５：３０：３５となるようにＡｌ２Ｏ３コロイドとＺｒ溶液とＣｅ溶液とを混合し、メタノールにより希釈して固形分濃度が１２質量％のコロイド溶液を調製した。そして、得られたコロイド溶液をホモジナイザにより２００００ｓｅｃ−１の剪断速度の下で２分間混合した後、約１分間緩やかな攪拌速度（２０ｒｐｍ）として混入気泡を除去せしめて被覆組成物を得た。
Example 1
Al 2 O 3 colloid, Zr solution, and Ce solution so that the mass ratio of Al 2 O 3 , ZrO 2, and CeO 2 in the resulting coating is Al 2 O 3 : ZrO 2 : CeO 2 = 35: 30: 35. And diluted with methanol to prepare a colloidal solution having a solid content concentration of 12% by mass. The resulting colloidal solution was mixed for 2 minutes with a homogenizer under a shear rate of 20000 sec −1 , and then mixed bubbles were removed at a gentle stirring speed (20 rpm) for about 1 minute to obtain a coating composition.
次に、前記の各基材を、上記で得られた被覆組成物に直ちに１〜１０秒間浸漬し、取り出してからその表面の余剰被覆組成物を重力及び振とうにより除去した。そして、その基材を水平に置いた後、常温による緩やかな乾燥を５〜１０分、風速２〜５ｍ／ｓの温風（６０〜１００℃）による乾燥を５〜１０分、空気雰囲気における２５０℃での仮焼成を約３０分施し、更に風速２〜５ｍ／ｓの常温風により５〜１０分冷却した。このような処理を２回繰り返した後に空気雰囲気において５００℃で約６０分間焼成し、基材表面に金属酸化物被覆が形成されている触媒担体を得た。 Next, each of the substrates was immediately immersed in the coating composition obtained above for 1 to 10 seconds, taken out, and then the excess coating composition on the surface was removed by gravity and shaking. And after placing the base material horizontally, 5-10 minutes of gentle drying at normal temperature, 5-10 minutes of drying with warm air (60-100 ° C.) at a wind speed of 2-5 m / s, 250 in an air atmosphere. Pre-baking at a temperature of about 30 minutes was performed, followed by cooling for 5 to 10 minutes with room temperature air at a wind speed of 2 to 5 m / s. Such a treatment was repeated twice, followed by firing at 500 ° C. for about 60 minutes in an air atmosphere to obtain a catalyst carrier having a metal oxide coating formed on the substrate surface.
得られた触媒担体における金属酸化物の被覆を透過型電子顕微鏡（ＴＥＭ）により観察したところ、被膜の厚さは約４μｍであり、非常に均一な金属酸化物からなる薄膜が形成されていることが確認された。 When the coating of the metal oxide on the obtained catalyst support was observed with a transmission electron microscope (TEM), the thickness of the coating was about 4 μm, and a thin film made of a very uniform metal oxide was formed. Was confirmed.
（比較例１）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例１と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 1)
A catalyst carrier having a metal oxide coating formed on the surface of the substrate is obtained in the same manner as in Example 1 except that instead of mixing with the homogenizer, the mixture is gently stirred with a propeller (shear rate of 10 sec −1 or less). It was.
（比較例２）
先ず、特開平１０−１８２１５５号公報（特許文献１）の実施例１に記載の共沈法により、従来のアルミナ／セリア／ジルコニア複合酸化物粉末を得た。次に、得られる金属酸化物薄膜におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝３５：３０：３５となるように従来のアルミナ／セリア／ジルコニア複合酸化物粉末とベーマイトと硝酸アルミとを混合した固形分濃度が７０質量％のスラリーを前記コロイド溶液に代えて用い、前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにし、さらに焼成温度を７００℃とした以外は実施例１と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 2)
First, a conventional alumina / ceria / zirconia composite oxide powder was obtained by the coprecipitation method described in Example 1 of JP-A-10-182155 (Patent Document 1). Next, conventional alumina / ceria so that the mass ratio of Al 2 O 3 , ZrO 2 and CeO 2 in the obtained metal oxide thin film is Al 2 O 3 : ZrO 2 : CeO 2 = 35: 30: 35. / Slurry mixed with zirconia composite oxide powder, boehmite and aluminum nitrate and having a solid concentration of 70% by mass is used in place of the colloidal solution, and gently mixed with a propeller instead of mixing with the homogenizer (shear rate 10 sec − 1 or less), and a catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 1 except that the calcination temperature was 700 ° C.
（実施例２〜５及び比較例３〜８）
Ａｌ２Ｏ３コロイドとＺｒ溶液とＺｒＯ２粉末とＣｅ溶液とを表１に示す割合（質量比）で混合するようにした以外は実施例１と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。なお、実施例２〜５及び比較例３〜８で得られた被覆の組成（表１中の組成Ｎｏ．）を図５に示す。図５において、斜線部が本発明の触媒担体における金属酸化物ナノ多孔体の組成に相当する。
(Examples 2-5 and Comparative Examples 3-8)
The substrate surface was coated with a metal oxide in the same manner as in Example 1 except that Al 2 O 3 colloid, Zr solution, ZrO 2 powder, and Ce solution were mixed at the ratio (mass ratio) shown in Table 1. A formed catalyst support was obtained. In addition, the composition (composition No. in Table 1) of the coating obtained in Examples 2-5 and Comparative Examples 3-8 is shown in FIG. In FIG. 5, the shaded area corresponds to the composition of the metal oxide nanoporous material in the catalyst carrier of the present invention.
（比較例９）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例５と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 9)
A catalyst carrier in which a metal oxide coating is formed on the surface of the substrate is obtained in the same manner as in Example 5 except that instead of mixing with the homogenizer, the mixture is gently stirred with a propeller (shear rate of 10 sec −1 or less). It was.
（実施例６）
得られる金属酸化物薄膜におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝４０：４０：２０となるようにＡｌ２Ｏ３コロイドとＺｒ溶液とＣｅ溶液とを混合するようにした以外は実施例１と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 6)
Al 2 O 3 colloid and Zr solution so that the mass ratio of Al 2 O 3 , ZrO 2 and CeO 2 in the obtained metal oxide thin film is Al 2 O 3 : ZrO 2 : CeO 2 = 40: 40: 20. A catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 1 except that the solution was mixed with the Ce solution.
（実施例７）
前記ホモジナイザによる混合の際の剪断速度が１００００ｓｅｃ−１となるようにした以外は実施例６と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 7)
A catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 6 except that the shear rate during mixing with the homogenizer was 10000 sec −1 .
（実施例８）
前記ホモジナイザによる混合の際の剪断速度が４０００ｓｅｃ−１となるようにした以外は実施例６と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 8)
A catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 6 except that the shear rate during mixing with the homogenizer was 4000 sec −1 .
（比較例１０）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度：１０ｓｅｃ−１以下）するようにした以外は実施例６と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 10)
A catalyst carrier in which a metal oxide coating is formed on the surface of a base material in the same manner as in Example 6 except that instead of mixing with the homogenizer, the mixture is gently stirred with a propeller (shear rate: 10 sec −1 or less). Obtained.
（実施例９）
得られる金属酸化物粉末におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝４０：４０：２０となるようにＡｌ２Ｏ３コロイドとＺｒ溶液とＣｅ溶液とを混合し、メタノールにより希釈して固形分濃度が１２質量％のコロイド溶液を調製した。そして、得られたコロイド溶液をホモジナイザにより２００００ｓｅｃ−１の剪断速度の下で２分間混合した後、約１分間緩やかな攪拌速度（20rpm）として混入気泡を除去せしめて被覆組成物を得た。
Example 9
Al 2 O 3 colloid and Zr solution so that the mass ratio of Al 2 O 3 , ZrO 2 and CeO 2 in the obtained metal oxide powder is Al 2 O 3 : ZrO 2 : CeO 2 = 40: 40: 20. And Ce solution were mixed and diluted with methanol to prepare a colloidal solution having a solid concentration of 12% by mass. The resulting colloidal solution was mixed for 2 minutes with a homogenizer under a shear rate of 20000 sec −1 and then mixed bubbles were removed at a gentle stirring speed (20 rpm) for about 1 minute to obtain a coating composition.
次に、得られた被覆組成物を１５０℃に加熱して水蒸気を除去し、更に２５０℃に加熱して硝酸成分を除去した後、乳鉢で粉砕して平均粒径が約７０μｍの金属酸化物粉体を得た。 Next, the obtained coating composition is heated to 150 ° C. to remove water vapor, further heated to 250 ° C. to remove the nitric acid component, and then ground in a mortar to obtain a metal oxide having an average particle size of about 70 μm. A powder was obtained.
（比較例１１）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例９と同様にして金属酸化物粉体を得た。
(Comparative Example 11)
A metal oxide powder was obtained in the same manner as in Example 9, except that instead of mixing with the homogenizer, the mixture was gently stirred with a propeller (shear rate of 10 sec −1 or less).
（実施例１０）
得られる被覆におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝３０：３０：４０となるように、Ａｌ溶液５５．２ｇ、Ｚｒ溶液１６．７ｇ及びＣｅ溶液１４．３ｇをメタノール１３．９ｇと混合し、固形分濃度が１０質量％の金属塩溶液を調製した。そして、得られた金属塩溶液をホモジナイザにより２００００ｓｅｃ−１の剪断速度の下で２分間混合した後、約１分間緩やかな攪拌速度（２０ｒｐｍ）として混入気泡を除去せしめて被覆組成物を得た。
(Example 10)
In the resulting coating, 55.2 g of Al solution and 16.2 Zr solution so that the mass ratio of Al 2 O 3 , ZrO 2 and CeO 2 is Al 2 O 3 : ZrO 2 : CeO 2 = 30: 30: 40. 7 g and 14.3 g of the Ce solution were mixed with 13.9 g of methanol to prepare a metal salt solution having a solid content concentration of 10% by mass. The obtained metal salt solution was mixed with a homogenizer at a shear rate of 20000 sec −1 for 2 minutes, and then mixed bubbles were removed at a gentle stirring speed (20 rpm) for about 1 minute to obtain a coating composition.
次に、予め１０００℃、１時間の熱処理を施してその表面に酸化被膜を形成せしめてある金属プレートを、上記で得られた被覆組成物に直ちに１〜１０秒間浸漬し、取り出してからその表面の余剰被覆組成物を重力及び振とうにより除去した。そして、そのプレートを水平に置いた後、常温による緩やかな乾燥を５〜１０分、風速２〜５ｍ／ｓの温風（６０〜１００℃）による乾燥を５〜１０分、空気雰囲気における２５０℃での仮焼成を約３０分施し、更に風速２〜５ｍ／ｓの常温風により５〜１０分冷却した。このような処理を２回繰り返した後に空気雰囲気において５００℃で約６０分間焼成し、評価プレート１枚に対して金属酸化物の被覆量が約０．２ｇとなっている触媒担体を得た。 Next, a metal plate that has been preliminarily subjected to heat treatment at 1000 ° C. for 1 hour to form an oxide film on the surface is immediately immersed in the coating composition obtained above for 1 to 10 seconds, taken out, and then its surface is removed. The excess coating composition was removed by gravity and shaking. And after placing the plate horizontally, gentle drying at room temperature for 5 to 10 minutes, drying with warm air (60 to 100 ° C.) at a wind speed of 2 to 5 m / s for 5 to 10 minutes, and 250 ° C. in an air atmosphere. For about 30 minutes, and further cooled for 5 to 10 minutes with room temperature air at a wind speed of 2 to 5 m / s. Such a treatment was repeated twice, followed by firing at 500 ° C. for about 60 minutes in an air atmosphere to obtain a catalyst carrier having a metal oxide coating amount of about 0.2 g per one evaluation plate.
得られた触媒担体における金属酸化物の被覆を透過型電子顕微鏡（ＴＥＭ）により観察したところ、被膜の厚さは約４μｍであり、非常に均一な金属酸化物からなる薄膜が形成されていることが確認された。 When the coating of the metal oxide on the obtained catalyst support was observed with a transmission electron microscope (TEM), the thickness of the coating was about 4 μm, and a thin film made of a very uniform metal oxide was formed. Was confirmed.
（比較例１２）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例１０と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 12)
A catalyst carrier in which a metal oxide coating is formed on the surface of the substrate is obtained in the same manner as in Example 10 except that instead of mixing with the homogenizer, the mixture is gently stirred with a propeller (shear rate of 10 sec −1 or less). It was.
（実施例１１）
得られる金属酸化物薄膜におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝４０：４０：２０となるようにＡｌ溶液とＺｒ溶液とＣｅ溶液とを混合するようにした以外は実施例１０と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 11)
The Al solution, the Zr solution, and the Ce solution so that the mass ratio of Al 2 O 3 , ZrO 2, and CeO 2 in the obtained metal oxide thin film is Al 2 O 3 : ZrO 2 : CeO 2 = 40: 40: 20. A catalyst support having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 10 except that the above was mixed.
（比較例１３）
前記ホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例１１と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Comparative Example 13)
A catalyst carrier having a metal oxide coating formed on the surface of the substrate is obtained in the same manner as in Example 11 except that instead of the mixing by the homogenizer, the mixture is gently stirred with a propeller (shear rate of 10 sec −1 or less). It was.
（実施例１２）
前記ホモジナイザによる混合の際の剪断速度が１００００ｓｅｃ−１となるようにした以外は実施例１０と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 12)
A catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 10 except that the shear rate during mixing by the homogenizer was 10,000 sec −1 .
（実施例１３）
前記ホモジナイザによる混合の際の剪断速度が４０００ｓｅｃ−１となるようにした以外は実施例１０と同様にして基材表面に金属酸化物被覆が形成されている触媒担体を得た。
(Example 13)
A catalyst carrier having a metal oxide coating formed on the substrate surface was obtained in the same manner as in Example 10 except that the shear rate during mixing with the homogenizer was 4000 sec- 1 .
（実施例１４）
得られる被覆におけるＡｌ２Ｏ３とＺｒＯ２とＣｅＯ２との質量比がＡｌ２Ｏ３：ＺｒＯ２：ＣｅＯ２＝３０：３０：４０となるように、Ａｌ溶液５５．２ｇ、Ｚｒ溶液１６．７ｇ及びＣｅ溶液１４．３ｇをメタノール１３．９ｇと混合し、固形分濃度が１０質量％の金属塩溶液を調製した。そして、得られた金属塩溶液をホモジナイザにより２００００ｓｅｃ−１の剪断速度の下で２分間混合した後、約１分間緩やかな攪拌速度（２０ｒｐｍ）として混入気泡を除去せしめて被覆組成物を得た。
(Example 14)
In the resulting coating, 55.2 g of Al solution and 16.2 Zr solution so that the mass ratio of Al 2 O 3 , ZrO 2 and CeO 2 is Al 2 O 3 : ZrO 2 : CeO 2 = 30: 30: 40. 7 g and 14.3 g of the Ce solution were mixed with 13.9 g of methanol to prepare a metal salt solution having a solid content concentration of 10% by mass. The obtained metal salt solution was mixed with a homogenizer at a shear rate of 20000 sec −1 for 2 minutes, and then mixed bubbles were removed at a gentle stirring speed (20 rpm) for about 1 minute to obtain a coating composition.
次に、得られた被覆組成物を３００〜３５０℃に加熱した高温プレート上に塗布し、３０分で乾燥（溶媒の除去）及び焼成（硝酸成分の除去及び金属成分の酸化）せしめた後、乳鉢で粉砕して平均粒径が約７０μｍの金属酸化物粉体を得た。 Next, after coating the obtained coating composition on a high-temperature plate heated to 300 to 350 ° C., drying (removing the solvent) and firing (removing the nitric acid component and oxidizing the metal component) in 30 minutes, By pulverizing in a mortar, metal oxide powder having an average particle size of about 70 μm was obtained.
（比較例１４）
前記金属塩溶液をホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例１４と同様にして金属酸化物粉体を得た。
(Comparative Example 14)
A metal oxide powder was obtained in the same manner as in Example 14 except that the metal salt solution was mixed gently with a propeller instead of being mixed with a homogenizer (shear rate of 10 sec −1 or less).
（実施例１５）
前記被覆組成物を空気雰囲気において５００℃で３〜４時間かけて乾燥及び焼成せしめるようにした以外は実施例１４と同様にして複合金属酸化物粉体を得た。
(Example 15)
A composite metal oxide powder was obtained in the same manner as in Example 14 except that the coating composition was dried and fired at 500 ° C. for 3 to 4 hours in an air atmosphere.
（比較例１５）
前記金属塩溶液をホモジナイザによる混合に代えてプロペラによりゆるやかに攪拌（剪断速度１０ｓｅｃ−１以下）するようにした以外は実施例１５と同様にして複合金属酸化物粉体を得た。
(Comparative Example 15)
A composite metal oxide powder was obtained in the same manner as in Example 15 except that the metal salt solution was mixed gently with a propeller instead of being mixed with a homogenizer (shear rate of 10 sec −1 or less).
＜成分均一性の評価１：条件(I)＞
先ず、実施例１、６、１１及び比較例１、１０、１３に記載の方法で得られた金属酸化物被覆並びに実施例９、１４、及び比較例２、１１、１４に記載の方法で得られた金属酸化物粉末について、以下のようにして成分均一性を評価した。すなわち、前述の条件(I)の測定方法にしたがって、これらの金属酸化物被覆及び金属酸化物粉末について加速電圧２００ｋＶ、電子ビーム径１．０ｎｍの透過型電子顕微鏡（日本電子社製、ＪＥＭ２０１０ＦＥＦ）を用いてエネルギー分散型Ｘ線分光法によりスペクトルを求め、薄膜に含有されるＡｌ、Ｚｒ及びＣｅについての蛍光Ｘ線ピークの積分強度を求めた。
<Evaluation of component uniformity 1: Condition (I)>
First, the metal oxide coatings obtained by the methods described in Examples 1, 6, 11 and Comparative Examples 1, 10, 13 and the methods described in Examples 9, 14 and Comparative Examples 2, 11, 14 were obtained. About the obtained metal oxide powder, the component uniformity was evaluated as follows. That is, according to the measurement method of the condition (I) described above, a transmission electron microscope (JEM2010 FEF, manufactured by JEOL Ltd.) having an acceleration voltage of 200 kV and an electron beam diameter of 1.0 nm is applied to these metal oxide coating and metal oxide powder. The spectrum was obtained by energy dispersive X-ray spectroscopy, and the integrated intensity of fluorescent X-ray peaks for Al, Zr and Ce contained in the thin film was obtained.
なお、透過型電子顕微鏡観察の際に、試料の厚さに関し、ＥＤＸ検出器で得られる全Ｘ線の総カウント数を基準とし、１万カウントから６万カウントの間になる部分を測定に適正な領域、すなわち被検試料の厚さが略一定とみなせる領域として採用した。 When observing with a transmission electron microscope, with regard to the thickness of the sample, using the total count of all X-rays obtained with the EDX detector as a reference, the portion between 10,000 count and 60,000 count is appropriate for measurement. This area was adopted as an area where the thickness of the test sample can be regarded as substantially constant.
そして、その測定結果に基づいて前述の相対強度比Ｘ、その平均値Ｘｍ、平均値Ｘｍのまわりの二次のモーメントν２、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を順次算出し、前記式（１）で表される条件を満たしているか否かを判定した。 Then, the relative intensity ratio X mentioned above based on the measurement result, the average value X m, average second moment [nu 2 around X m, second moment normalized by the square of the mean value X m [nu 2 / X m 2 was sequentially calculated, and it was determined whether or not the condition represented by the formula (1) was satisfied.
このようにして得られた平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を表２にそれぞれ示す。 Table 2 shows secondary moments ν 2 / X m 2 normalized by the square of the average value X m thus obtained.
表２に示した結果から明らかな通り、本発明の方法で得られた実施例１、６、１１で得られた金属酸化物被覆及び実施例９、１４で得られた金属酸化物粉体においては、金属酸化物に含有される金属元素のすべてについて前記式（１）で表される条件が満たされており、金属酸化物が極めて均一に分散していることが確認された。一方、高速剪断速度の下での混合をしなかった比較例１、１０、１３で得られた金属酸化物被覆及び比較例１１、１４で得られた金属酸化物粉体においては、粉体に含有される金属元素のすべてについて前記式（１）で表される条件が満たされていないことが確認された。さらに、比較例２で得られた従来の共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末においても、粉体に含有される金属元素のほとんどについて前記式（１）で表される条件が満たされていないことが確認された。 As is clear from the results shown in Table 2, in the metal oxide coatings obtained in Examples 1, 6, and 11 obtained by the method of the present invention and the metal oxide powders obtained in Examples 9 and 14, As for all the metal elements contained in the metal oxide, the condition represented by the above formula (1) was satisfied, and it was confirmed that the metal oxide was very uniformly dispersed. On the other hand, in the metal oxide coating obtained in Comparative Examples 1, 10, and 13 and the metal oxide powder obtained in Comparative Examples 11 and 14 that were not mixed under a high shear rate, It was confirmed that the conditions represented by the formula (1) were not satisfied for all of the contained metal elements. Further, in the conventional alumina / ceria / zirconia composite oxide powder obtained by the conventional coprecipitation method obtained in Comparative Example 2, most of the metal elements contained in the powder are represented by the above formula (1). It was confirmed that the conditions to be met were not met.
＜成分均一性の評価２：条件(II)＞
先ず、実施例１に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約５μｍ）について、以下のようにして成分均一性を評価した。すなわち、実施例１で得られた被覆の表面に任意に０．５ｍｍの測定直線を２本設定し（測定直線１及び測定直線２）、被覆に含有されるＡｌ、Ｚｒ及びＣｅと基材に含有されるＦｅとについて、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザー（日本電子社製、ＪＸＡ−８２００）を用いて前記測定直線上の測定点において線分析し、各測定点におけるＫ値（K-value）、全測定点におけるＫ値の平均値（Ｋｍ）、及び各測定点における｛｜Ｋ−Ｋｍ｜／Ｋｍ｝の値を求めた。なお、亀裂に相当する部分については、基材に含有されるＦｅが検出されるか否かで判定した。測定直線１について得られた結果を表３に、測定直線２について得られた結果を表４にそれぞれ示す。
<Evaluation of component uniformity 2: Condition (II)>
First, the component uniformity of the metal oxide coating (film thickness: about 5 μm) formed on the surface of the metal plate by the method described in Example 1 was evaluated as follows. That is, two measurement lines of 0.5 mm are arbitrarily set on the surface of the coating obtained in Example 1 (measurement line 1 and measurement line 2), and Al, Zr, and Ce contained in the coating and the substrate The Fe contained is subjected to line analysis at measurement points on the measurement line using an X-ray microanalyzer (manufactured by JEOL Ltd., JXA-8200) having an acceleration voltage of 15 kV and an electron beam diameter of 1 μm, and K at each measurement point. A value (K-value), an average value (K m ) of K values at all measurement points, and a value of {| K−K m | / K m } at each measurement point were obtained. In addition, about the part corresponded to a crack, it determined by whether Fe contained in a base material was detected. The results obtained for measurement line 1 are shown in Table 3, and the results obtained for measurement line 2 are shown in Table 4, respectively.
表３及び表４に示した結果から明らかな通り、コロイド溶液を高剪断速度の下で混合した後に基材に塗布して高速で乾燥及び焼成して得た実施例１で得られた金属酸化物被覆においては、被覆に含有される金属元素のすべてについて、全測定点のうちの６５％以上の測定点において前記式（３）で表される条件が満たされており、金属酸化物が被覆中で極めて均一に分散していることが確認された。 As is clear from the results shown in Tables 3 and 4, the metal oxide obtained in Example 1 obtained by mixing the colloidal solution at a high shear rate, applying the colloidal solution to the substrate, drying at high speed and firing. In the object coating, for all of the metal elements contained in the coating, the condition represented by the above formula (3) is satisfied at 65% or more of the total measurement points, and the metal oxide is coated. It was confirmed that the dispersion was extremely uniform.
次に、比較例１に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約５μｍ）について、上記と同様にして成分均一性を評価した。すなわち、比較例１で得られた被覆の表面に任意に０．５ｍｍの測定直線を２本設定し（測定直線１及び測定直線２）、被覆に含有されるＡｌ、Ｚｒ及びＣｅと基材に含有されるＦｅとについて上記と同様にして線分析し、各測定点におけるＫ値（K-value）、全測定点におけるＫ値の平均値（Ｋｍ）、及び各測定点における｛｜Ｋ−Ｋｍ｜／Ｋｍ｝の値を求めた。測定直線１について得られた結果を表５に、測定直線２について得られた結果を表６にそれぞれ示す。 Next, the component uniformity was evaluated in the same manner as described above for the metal oxide coating (film thickness: about 5 μm) formed on the surface of the metal plate by the method described in Comparative Example 1. That is, two measurement lines of 0.5 mm are arbitrarily set on the surface of the coating obtained in Comparative Example 1 (measurement line 1 and measurement line 2), and Al, Zr, and Ce contained in the coating and the substrate The Fe content is analyzed in the same manner as described above, and the K value (K-value) at each measurement point, the average value (K m ) of the K values at all measurement points, and {| K- The value of K m | / K m } was determined. The results obtained for measurement line 1 are shown in Table 5, and the results obtained for measurement line 2 are shown in Table 6, respectively.
表５及び表６に示した結果から明らかな通り、コロイド溶液をそのまま用いた比較例１で得られた金属酸化物被覆においては、被覆に含有される金属元素のうち少なくとも一部について、前記式（３）で表される条件が満たされている測定点の割合が６５％を下回っていることが確認された。 As is clear from the results shown in Tables 5 and 6, in the metal oxide coating obtained in Comparative Example 1 using the colloidal solution as it is, at least a part of the metal elements contained in the coating is represented by the above formula. It was confirmed that the proportion of measurement points satisfying the condition represented by (3) was less than 65%.
次に、比較例２に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約４０μｍ）について、上記と同様にして成分均一性を評価した。なお、比較例２に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆は基材に対する付着性が明らかに劣っており、膜厚を４０μｍ程度にしないと基材を覆う被覆にはならなかった。すなわち、比較例２で得られた金属酸化物被覆の表面に任意に０．５ｍｍの測定直線を２本設定し（測定直線１及び測定直線２）、被覆に含有されるＡｌ、Ｚｒ及びＣｅと基材に含有されるＦｅとについて上記と同様にして線分析し、各測定点におけるＫ値（K-value）、全測定点におけるＫ値の平均値（Ｋｍ）、及び各測定点における｛｜Ｋ−Ｋｍ｜／Ｋｍ｝の値を求めた。測定直線１について得られた結果を表７に、測定直線２について得られた結果を表８にそれぞれ示す。 Next, component uniformity was evaluated in the same manner as described above for the metal oxide coating (film thickness: about 40 μm) formed on the surface of the metal plate by the method described in Comparative Example 2. In addition, the metal oxide coating formed on the surface of the metal plate by the method described in Comparative Example 2 is clearly inferior in adhesion to the substrate, and unless the film thickness is about 40 μm, the coating covering the substrate is used. I didn't. That is, two measurement lines of 0.5 mm were arbitrarily set on the surface of the metal oxide coating obtained in Comparative Example 2 (measurement line 1 and measurement line 2), and Al, Zr, and Ce contained in the coating The Fe contained in the base material was subjected to line analysis in the same manner as described above, and the K value (K-value) at each measurement point, the average value (K m ) of the K values at all measurement points, and { The value of | K−K m | / K m } was determined. The results obtained for measurement line 1 are shown in Table 7, and the results obtained for measurement line 2 are shown in Table 8, respectively.
表７及び表８に示した結果から明らかな通り、共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末を含有するスラリーをそのまま用いた比較例２で得られた金属酸化物被覆においては、被覆に含有される金属元素のすべてについて、前記式（３）で表される条件が満たされている測定点の割合が６５％を下回っていることが確認された。 As is apparent from the results shown in Tables 7 and 8, the metal oxide obtained in Comparative Example 2 using the slurry containing the conventional alumina / ceria / zirconia composite oxide powder obtained by the coprecipitation method as it was. In the coating, it was confirmed that the ratio of the measurement points satisfying the condition represented by the formula (3) was less than 65% for all the metal elements contained in the coating.
＜表面形状の評価：条件(III)＞
先ず、実施例１に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約５μｍ）について、以下のようにして表面形状を評価した。すなわち、実施例１で得られた金属酸化物被覆の表面に任意に２μｍの測定直線を設定し（５１２点計測、３．９１ｎｍ間隔）、走査型プローブ顕微鏡（Digital Instruments社製 NanoScope IIIa、NanoAnalytics社製 Ｑコントロールモジュール付き）にて５ｎｍの曲率半径を有するスーパーシャープチップを用いて被覆表面の高さ像をタッピングモードで計測し、走査距離Ｌの関数として高さ像Ｈ（Ｌ）及びその二次微係数Ｈ”（Ｌ）を求めた。その結果、コロイド溶液を高剪断速度の下で混合した後に基材に塗布して高速で乾燥及び焼成して得た実施例１で得られた金属酸化物被覆においては、全測定点のうちの９４％の測定点において高さ像Ｈ（Ｌ）が２０ｎｍ以下であり、被覆の表面が細かい凹凸状態であることが確認された。また、実施例１で得られた金属酸化物被覆においては、二次微係数Ｈ”（Ｌ）の絶対値が０．０５ｎｍ−１以下の測定点の割合が５４％であり、被覆の表面凹凸の上に更に非常に細かい小突起が多い状態であることが確認された。
<Evaluation of surface shape: Condition (III)>
First, the surface shape of the metal oxide coating (film thickness: about 5 μm) formed on the surface of the metal plate by the method described in Example 1 was evaluated as follows. That is, a measurement line of 2 μm was arbitrarily set on the surface of the metal oxide coating obtained in Example 1 (512 point measurement, 3.91 nm interval), and a scanning probe microscope (NanoScope IIIa manufactured by Digital Instruments, NanoAnalytics) The height image of the coated surface is measured in a tapping mode using a super sharp tip having a radius of curvature of 5 nm with a Q control module, and the height image H (L) and its secondary as a function of the scanning distance L The differential coefficient H ″ (L) was determined. As a result, the metal oxide obtained in Example 1 obtained by mixing the colloidal solution at a high shear rate, applying it to the substrate, drying and firing at high speed, and the like. In the object coating, the height image H (L) was 20 nm or less at 94% of the measurement points, and it was confirmed that the surface of the coating was in a fine uneven state. Got in In metal oxide-coated, the absolute value of the secondary differential coefficient H "(L) is a ratio of 54% 0.05 nm -1 or less measurement points further very fine small on the surface irregularities of the coating It was confirmed that there were many protrusions.
次に、比較例１に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約５μｍ）について、上記と同様にして表面形状を評価した。すなわち、比較例１で得られた金属酸化物被覆の表面の高さ像を上記と同様にして計測し、走査距離Ｌの関数として高さ像Ｈ（Ｌ）及びその二次微係数Ｈ”（Ｌ）を求めた。その結果、コロイド溶液をそのまま用いた比較例１で得られた金属酸化物被覆においては、全測定点のうちの９４％の測定点において高さ像Ｈ（Ｌ）が２０ｎｍ以下であったものの、二次微係数Ｈ”（Ｌ）の絶対値が０．０５ｎｍ−１以下の測定点の割合が７０％であり、被覆の表面の凹凸が比較的滑らかであることが確認された。 Next, the surface shape of the metal oxide coating (film thickness: about 5 μm) formed on the surface of the metal plate by the method described in Comparative Example 1 was evaluated in the same manner as described above. That is, the height image of the surface of the metal oxide coating obtained in Comparative Example 1 was measured in the same manner as described above, and the height image H (L) and its second derivative H ″ ( As a result, in the metal oxide coating obtained in Comparative Example 1 using the colloidal solution as it was, the height image H (L) was 20 nm at 94% of the measurement points. Although it was below, the ratio of the measurement points where the absolute value of the secondary differential coefficient H ″ (L) was 0.05 nm −1 or less was 70%, and it was confirmed that the unevenness on the surface of the coating was relatively smooth. It was done.
次に、比較例２に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆（膜厚：約４０μｍ）について、上記と同様にして表面形状を評価した。すなわち、比較例２で得られた金属酸化物被覆の表面の高さ像を上記と同様にして計測し、走査距離Ｌの関数として高さ像Ｈ（Ｌ）及びその二次微係数Ｈ”（Ｌ）を求めた。その結果、共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末を含有するスラリーをそのまま用いた比較例２で得られた金属酸化物被覆においては、高さ像Ｈ（Ｌ）が２０ｎｍ以下の測定点の割合が４４％であり、且つ、二次微係数Ｈ”（Ｌ）の絶対値が０．０５ｎｍ−１以下の測定点の割合が６１％であり、被覆の表面には比較的滑らかで大きな凹凸があることが確認された。 Next, the surface shape of the metal oxide coating (film thickness: about 40 μm) formed on the surface of the metal plate by the method described in Comparative Example 2 was evaluated in the same manner as described above. That is, the height image of the surface of the metal oxide coating obtained in Comparative Example 2 was measured in the same manner as described above, and the height image H (L) and its second derivative H ″ ( As a result, in the metal oxide coating obtained in Comparative Example 2 in which the slurry containing the conventional alumina / ceria / zirconia composite oxide powder obtained by the coprecipitation method was used as it was, The ratio of measurement points with a height H (L) of 20 nm or less is 44%, and the ratio of measurement points with an absolute value of the second derivative H ″ (L) of 0.05 nm −1 or less is 61%. It was confirmed that the surface of the coating was relatively smooth and had large irregularities.
＜断面性状の評価：条件(IV)＞
先ず、実施例１に記載の方法で前記４００メッシュのハニカム形状を有するコージエライト基板の端部に形成せしめた金属酸化物被覆について、以下のようにして断面性状を評価した。すなわち、実施例１で得られた金属酸化物被覆の断面の電子顕微鏡写真において、前記被覆の上に総計で４６５．５μｍの４本の測定直線（line１〜４）を描き、これらの測定直線が前記被覆に形成されている空隙部と交差している部分の長さの比率を求めた。その結果、コロイド溶液を高剪断速度の下で混合した後に基材に塗布して高速で乾燥及び焼成して得た実施例１で得られた金属酸化物被覆においては、前記測定直線が空隙部と交差している部分の長さの比率は４．３％であり、被覆を構成する金属酸化物において連続性が確保されており被覆中に空隙が少ないことが確認された。
<Evaluation of sectional properties: Condition (IV)>
First, the cross-sectional properties of the metal oxide coating formed on the end portion of the cordierite substrate having the 400-mesh honeycomb shape by the method described in Example 1 were evaluated as follows. That is, in the electron micrograph of the cross section of the metal oxide coating obtained in Example 1, four measurement lines (lines 1 to 4) of 465.5 μm in total were drawn on the coating, and these measurement lines were The ratio of the length of the part which cross | intersects the space | gap part currently formed in the said coating | cover was calculated | required. As a result, in the metal oxide coating obtained in Example 1 obtained by mixing the colloidal solution at a high shear rate, applying it to the substrate, drying and firing at a high speed, the measurement straight line has a void portion. The ratio of the length of the part intersecting with the metal was 4.3%, and it was confirmed that continuity was ensured in the metal oxide constituting the coating, and there were few voids in the coating.
次に、比較例２に記載の方法で前記４００メッシュのハニカム形状を有するコージエライト基板の端部に形成せしめた金属酸化物被覆について、上記と同様にして断面性状を評価した。すなわち、比較例２で得られた金属酸化物被覆の断面の電子顕微鏡写真において、前記被覆の上に総計で５５６．０μｍの４本の測定直線（line１〜４）を描き、これらの測定直線が前記被覆に形成されている空隙部と交差している部分の長さの比率を求めた。その結果、共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末を含有するスラリーをそのまま用いた比較例２で得られた金属酸化物被覆においては、前記測定直線が空隙部と交差している部分の長さの比率は４２．４％であり、被覆中に空隙が多いことが確認された。 Next, the cross-sectional properties of the metal oxide coating formed on the end portion of the cordierite substrate having the 400-mesh honeycomb shape by the method described in Comparative Example 2 were evaluated in the same manner as described above. That is, in the electron micrograph of the cross section of the metal oxide coating obtained in Comparative Example 2, four measurement lines (lines 1 to 4) of 556.0 μm in total were drawn on the coating, and these measurement lines were The ratio of the length of the part which cross | intersects the space | gap part currently formed in the said coating | cover was calculated | required. As a result, in the metal oxide coating obtained in Comparative Example 2 using the slurry containing the conventional alumina / ceria / zirconia composite oxide powder obtained by the coprecipitation method, the measurement line is The ratio of the length of the intersecting portions was 42.4%, and it was confirmed that there were many voids in the coating.
＜成分均一性の評価３：条件(V)＞
先ず、実施例１４に記載の方法で得られた金属酸化物粉体について、以下のようにして成分均一性を評価した。すなわち、前述の測定方法にしたがって、実施例１４で得られた金属酸化物粉体の透過型電子顕微鏡写真における測定点（１０箇所の良好な測定部位）において、加速電圧２００ｋＶ、電子ビーム径１．０ｎｍの透過型電子顕微鏡（日本電子社製、ＪＥＭ２０１０ＦＥＦ）を用いてエネルギー分散型Ｘ線分光法によりスペクトルを求め、粉体に含有されるＡｌ、Ｚｒ及びＣｅについての蛍光Ｘ線ピークの積分強度を求めた。そして、その測定結果に基づいて前述の相対強度比Ｘ、その平均値Ｘｍ、平均値Ｘｍのまわりの二次のモーメントν２、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を順次算出し、前記式（８）で表される条件を満たしているか否かを判定した。
<Evaluation of component uniformity 3: Condition (V)>
First, the component uniformity of the metal oxide powder obtained by the method described in Example 14 was evaluated as follows. That is, according to the measurement method described above, at a measurement point (10 good measurement sites) in the transmission electron micrograph of the metal oxide powder obtained in Example 14, an acceleration voltage of 200 kV, an electron beam diameter of 1. A spectrum is obtained by energy dispersive X-ray spectroscopy using a transmission electron microscope of 0 nm (manufactured by JEOL Ltd., JEM2010FEF), and the integrated intensity of fluorescent X-ray peaks for Al, Zr and Ce contained in the powder is obtained. Asked. Then, the relative intensity ratio X mentioned above based on the measurement result, the average value X m, average second moment [nu 2 around X m, second moment normalized by the square of the mean value X m [nu 2 / X m 2 was sequentially calculated, and it was determined whether or not the condition represented by the formula (8) was satisfied.
実施例１４の金属酸化物粉体について得られた各測定点（Homo-01〜Homo-10）における蛍光Ｘ線ピークの積分強度比Ｘを表９に、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を表１０にそれぞれ示す。 The integrated intensity ratio X of the fluorescent X-ray peaks are listed in Table 9 at each measurement point obtained for the metal oxide powder of Example 14 (Homo-01~Homo-10) , normalized by the square of the mean value X m The secondary moments ν 2 / X m 2 are shown in Table 10, respectively.
表１０に示した結果から明らかな通り、金属塩溶液を高剪断速度の下で混合した後に高速で乾燥及び焼成して得た実施例１４で得られた金属酸化物粉体においては、粉体に含有される金属元素のすべてについて前記式（８）で表される条件が満たされており、金属酸化物が粉体中で極めて均一に分散していることが確認された。 As is apparent from the results shown in Table 10, in the metal oxide powder obtained in Example 14 obtained by mixing and drying the metal salt solution at a high shear rate and then drying and firing at high speed, the powder It was confirmed that the conditions represented by the above formula (8) were satisfied for all of the metal elements contained in the metal element, and the metal oxide was very uniformly dispersed in the powder.
次に、比較例１４に記載の方法で得られた金属酸化物粉体について、上記と同様にして成分均一性を評価した。すなわち、比較例１４で得られた金属酸化物粉体の測定点（１５箇所の良好な測定部位）においてエネルギー分散型Ｘ線分光法によりスペクトルを求め、粉体に含有されるＡｌ、Ｚｒ及びＣｅについての蛍光Ｘ線ピークの積分強度を求めた。そして、その測定結果に基づいて前述の相対強度比Ｘ、その平均値Ｘｍ、平均値Ｘｍのまわりの二次のモーメントν２、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を順次算出し、前記式（８）で表される条件を満たしているか否かを判定した。 Next, the component uniformity of the metal oxide powder obtained by the method described in Comparative Example 14 was evaluated in the same manner as described above. That is, spectra were obtained by energy dispersive X-ray spectroscopy at the measurement points (15 good measurement sites) of the metal oxide powder obtained in Comparative Example 14, and Al, Zr and Ce contained in the powder were obtained. The integrated intensity of the fluorescent X-ray peak for was determined. Then, the relative intensity ratio X mentioned above based on the measurement result, the average value X m, average second moment [nu 2 around X m, second moment normalized by the square of the mean value X m [nu 2 / X m 2 was sequentially calculated, and it was determined whether or not the condition represented by the formula (8) was satisfied.
比較例１４の金属酸化物粉体について得られた各測定点（Non-Homo-01〜Non-Homo-15）における蛍光Ｘ線ピークの積分強度比Ｘを表１１に、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を表１０にそれぞれ示す。 The integrated intensity ratio X of the fluorescent X-ray peak at each measurement point obtained for the metal oxide powder in Comparative Example 14 (Non-Homo-01~Non- Homo-15) in Table 11, the square of the mean value X m Table 10 shows the secondary moments ν 2 / X m 2 normalized by.
表１０に示した結果から明らかな通り、金属塩溶液をそのまま用いた比較例１４で得られた金属酸化物粉体においては、粉体に含有される金属元素のすべてについて前記式（８）で表される条件が満たされていないことが確認された。 As is clear from the results shown in Table 10, in the metal oxide powder obtained in Comparative Example 14 using the metal salt solution as it is, all the metal elements contained in the powder are expressed by the above formula (8). It was confirmed that the conditions represented were not met.
次に、比較例２で得られた従来の共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末について、上記と同様にして成分均一性を評価した。すなわち、比較例２で得られた金属酸化物粉体の測定点（１５箇所の良好な測定部位）においてエネルギー分散型Ｘ線分光法によりスペクトルを求め、粉体に含有されるＡｌ、Ｚｒ及びＣｅについての蛍光Ｘ線ピークの積分強度を求めた。そして、その測定結果に基づいて前述の相対強度比Ｘ、その平均値Ｘｍ、平均値Ｘｍのまわりの二次のモーメントν２、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を順次算出し、前記式（８）で表される条件を満たしているか否かを判定した。 Next, the uniformity of the components of the conventional alumina / ceria / zirconia composite oxide powder obtained by the conventional coprecipitation method obtained in Comparative Example 2 was evaluated in the same manner as described above. That is, a spectrum was obtained by energy dispersive X-ray spectroscopy at the measurement points (15 good measurement sites) of the metal oxide powder obtained in Comparative Example 2, and Al, Zr, and Ce contained in the powder were obtained. The integrated intensity of the fluorescent X-ray peak for was determined. Then, the relative intensity ratio X mentioned above based on the measurement result, the average value X m, average second moment [nu 2 around X m, second moment normalized by the square of the mean value X m [nu 2 / X m 2 was sequentially calculated, and it was determined whether or not the condition represented by the formula (8) was satisfied.
比較例２の金属酸化物粉体について得られた各測定点（共沈-01〜共沈-15）における蛍光Ｘ線ピークの積分強度比Ｘを表１２に、平均値Ｘｍの二乗で規格化した二次のモーメントν２／Ｘｍ ２を表１０にそれぞれ示す。 The integrated intensity ratio X of the fluorescent X-ray peaks are listed in Table 12 at the respective measurement points obtained for the metal oxide powder of Comparative Example 2 (coprecipitation -01～ coprecipitation -15), standard the square of the mean value X m Table 10 shows the converted second moments ν 2 / X m 2 , respectively.
表１０に示した結果から明らかな通り、共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末においても、粉体に含有される金属元素のほとんどについて前記式（８）で表される条件が満たされていないことが確認された。 As is apparent from the results shown in Table 10, in the conventional alumina / ceria / zirconia composite oxide powder obtained by the coprecipitation method, most of the metal elements contained in the powder are expressed by the above formula (8). It was confirmed that the conditions to be met were not met.
＜成分均一性の評価４＞
実施例１０、１２、１３及び比較例１２に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物被覆について、以下のようにして成分均一性を評価した。すなわち、実施例１０、１２、１３及び比較例１２で得られた金属酸化物被覆の表面に任意に０．５ｍｍの測定直線を設定し、被覆に含有されるＡｌ、Ｚｒ及びＣｅと基材に含有されるＦｅとについて、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザー（日本電子社製、ＪＸＡ−８２００）を用いて前記測定直線上の測定点において線分析し、各測定点におけるＫ値（K-value）、全測定点におけるＫ値の平均値（Ｋｍ）、及び各測定点における｛｜Ｋ−Ｋｍ｜／Ｋｍ｝の値を求めた。なお、亀裂に相当する部分については、基材に含有されるＦｅが検出されるか否かで判定した。得られた結果を表１３及び図６に示す。
<Evaluation of component uniformity 4>
With respect to the metal oxide coating formed on the surface of the metal plate by the methods described in Examples 10, 12, 13 and Comparative Example 12, the component uniformity was evaluated as follows. That is, a measurement line of 0.5 mm is arbitrarily set on the surface of the metal oxide coating obtained in Examples 10, 12, 13 and Comparative Example 12, and the Al, Zr and Ce contained in the coating and the substrate The Fe contained is subjected to line analysis at measurement points on the measurement line using an X-ray microanalyzer (manufactured by JEOL Ltd., JXA-8200) having an acceleration voltage of 15 kV and an electron beam diameter of 1 μm, and K at each measurement point. A value (K-value), an average value (K m ) of K values at all measurement points, and a value of {| K−K m | / K m } at each measurement point were obtained. In addition, about the part corresponded to a crack, it determined by whether Fe contained in a base material was detected. The obtained results are shown in Table 13 and FIG.
また、実施例６〜８及び比較例１０に記載の方法で前記金属プレートの表面に形成せしめた金属酸化物薄膜についても同様に成分均一性を評価した。得られた結果を表１４及び図７に示す。 Moreover, the component uniformity was similarly evaluated about the metal oxide thin film formed on the surface of the said metal plate by the method of Examples 6-8 and Comparative Example 10. FIG. The obtained results are shown in Table 14 and FIG.
表１３〜１４及び図６〜７に示した結果から明らかな通り、原料流体組成物を混合する際の剪断速度が増加するにしたがって得られた金属酸化物薄膜における金属酸化物の均質分散性が向上し、特に剪断速度が１００００ｓｅｃ−１以上になると均質分散性が顕著に向上することが確認された。 As is apparent from the results shown in Tables 13 to 14 and FIGS. 6 to 7, the homogeneous dispersibility of the metal oxide in the metal oxide thin film obtained as the shear rate during mixing of the raw material fluid composition increases. In particular, it was confirmed that the homogeneous dispersibility was remarkably improved when the shear rate was 10,000 sec −1 or more.
＜耐熱性試験＞
実施例１及び比較例１、２に記載の方法で得られた金属酸化物被覆、実施例１４に記載の方法で得られた金属酸化物粉体、並びに比較例２で得られた従来の共沈法により得られた従来のアルミナ／セリア／ジルコニア複合酸化物粉末について、以下のようにして耐熱性を評価した。すなわち、各金属酸化物被覆及び金属酸化物粉体を酸化雰囲気（大気中）において５００℃、９００℃、１０００℃に加熱してそれぞれ５時間維持した後の比表面積（ＢＥＴ比表面積）を測定した。
<Heat resistance test>
The metal oxide coating obtained by the method described in Example 1 and Comparative Examples 1 and 2, the metal oxide powder obtained by the method described in Example 14, and the conventional co-polymer obtained in Comparative Example 2. The heat resistance of the conventional alumina / ceria / zirconia composite oxide powder obtained by the precipitation method was evaluated as follows. That is, the specific surface area (BET specific surface area) after each metal oxide coating and metal oxide powder was heated to 500 ° C., 900 ° C., and 1000 ° C. in an oxidizing atmosphere (in the atmosphere) and maintained for 5 hours was measured. .
得られた結果を図８及び図９に示す。図８及び図９に示した結果から明らかな通り、コロイド溶液又は金属塩溶液を高剪断速度の下で混合した後に高速で乾燥及び焼成して得た本発明の金属酸化物被覆及び金属酸化物粉体においては、特に５００℃及び９００℃における耐熱性が大幅に向上していることが確認された。 The obtained results are shown in FIGS. As is clear from the results shown in FIGS. 8 and 9, the metal oxide coating and metal oxide of the present invention obtained by mixing a colloidal solution or a metal salt solution at a high shear rate and then drying and firing at high speed. In the powder, it was confirmed that the heat resistance at 500 ° C. and 900 ° C. was greatly improved.
また、実施例１４、１５及び比較例１４、１５に記載の方法で得られた金属酸化物粉体について、以下のようにして耐熱性を評価した。すなわち、各金属酸化物粉体を酸化雰囲気（大気中）において９００℃に加熱して５時間維持した後の比表面積（ＢＥＴ比表面積）を測定した。得られた結果は以下の通りである。
実施例１４：ＢＥＴ比表面積＝６７．８ｍ２／ｇ
比較例１４：ＢＥＴ比表面積＝５４．９ｍ２／ｇ
実施例１５：ＢＥＴ比表面積＝５４．７ｍ２／ｇ
比較例１５：ＢＥＴ比表面積＝５４．０ｍ２／ｇ。
Further, the heat resistance of the metal oxide powders obtained by the methods described in Examples 14 and 15 and Comparative Examples 14 and 15 was evaluated as follows. That is, the specific surface area (BET specific surface area) after each metal oxide powder was heated to 900 ° C. in an oxidizing atmosphere (in the air) and maintained for 5 hours was measured. The results obtained are as follows.
Example 14: BET specific surface area = 67.8 m 2 / g
Comparative Example 14: BET specific surface area = 54.9 m 2 / g
Example 15: BET specific surface area = 54.7 m 2 / g
Comparative Example 15: BET specific surface area = 54.0 m 2 / g.
以上の結果から、金属塩溶液を高剪断速度の下で混合した後に高速で乾燥及び焼成して得た本発明の金属酸化物粉体においては、９００℃における耐熱性が大幅に向上していることが確認された。また、実施例１４の結果と実施例１５の結果とを比較すると、金属塩溶液を高剪断速度の下で混合した後に高速で乾燥及び焼成することによって、得られる金属酸化物粉体の耐熱性が大幅に向上することが確認された。 From the above results, the heat resistance at 900 ° C. is greatly improved in the metal oxide powder of the present invention obtained by mixing and drying the metal salt solution at a high shear rate and then drying and firing at high speed. It was confirmed. Moreover, when the result of Example 14 and the result of Example 15 are compared, the heat resistance of the metal oxide powder obtained by mixing the metal salt solution at a high shear rate and then drying and firing at high speed. Was confirmed to improve significantly.
＜改質特性試験＞
実施例２〜５及び比較例３〜８に記載の方法で前記金属製高密度ハニカムに金属酸化物被覆を担持せしめた触媒担体を用いて得た触媒について、以下のようにして改質特性を評価した。すなわち、先ず、金属酸化物被覆を担持せしめた各金属製高密度ハニカムをＲｈ溶液に１時間浸漬し、取り出してからその表面の余剰溶液を重力及び振とうにより除去した。そして、その金属製高密度ハニカムを水平に置いた後、常温による緩やかな乾燥を５〜１０分、風速２〜５ｍ／ｓの温風（６０〜１００℃）による乾燥を５〜１０分、空気雰囲気における３００℃での焼成を約６０分施し、更に風速２〜５ｍ／ｓの常温風により５〜１０分冷却した。このような処理を３回繰り返し、金属酸化物被覆を担持せしめた各金属製高密度ハニカムに０．１ｇのロジウムを担持せしめて水素生成反応用触媒を得た。
<Modification characteristics test>
With respect to the catalysts obtained by using the catalyst carrier having the metal high-density honeycomb supported on the metal high-density honeycomb by the methods described in Examples 2 to 5 and Comparative Examples 3 to 8, the reforming characteristics were as follows. evaluated. That is, first, each metal high-density honeycomb carrying a metal oxide coating was immersed in an Rh solution for 1 hour, taken out, and then the excess solution on the surface was removed by gravity and shaking. Then, after placing the metal high-density honeycomb horizontally, gentle drying at normal temperature for 5 to 10 minutes, drying with warm air (60 to 100 ° C.) at a wind speed of 2 to 5 m / s for 5 to 10 minutes, air Firing at 300 ° C. in an atmosphere was performed for about 60 minutes, and further, cooling was performed for 5 to 10 minutes with room temperature air at a wind speed of 2 to 5 m / s. Such a treatment was repeated three times, and 0.1 g of rhodium was loaded on each metal high-density honeycomb loaded with a metal oxide coating to obtain a hydrogen generation reaction catalyst.
次に、このようにして得られた各水素生成反応用触媒を、赤外線イメージ炉において加熱し、改質燃料としてイソオクタンを用い、空間速度２５０００ｈ−１、steam／carbon＝２、oxide／carbon＝０．１という条件で改質特性試験を実施した。また、温度条件としては出口温度を５５０℃に設定し、計測項目としては出口ガス成分（Ｈ２、ＣＯ、ＣＯ２、Ｎ２、ＣＨ４、ＨＣ、Ｈ２Ｏ）とし、各成分の出口ガス濃度に基づいて以下の式により転化率を計算した。得られた転化率を図１０に示す。また、出口ガス中のＨ２濃度及びＣＨ４濃度を図１１に示す。
転化率（％）＝（ＣＯ、ＣＯ２及びＣＨ４中のcarbon）／（イソオクタン中のcarbon）
図１０及び図１１に示した結果から明らかな通り、実施例２〜５及び比較例３〜８に記載の方法で得られた触媒担体を用いて得た本発明の水素生成反応用触媒においては、９２％以上の高転化率と４０質量％以上の高水素濃度とが同時に達成されており、非常に優れた改質特性を有するものであることが確認された。
Next, each hydrogen production reaction catalyst thus obtained is heated in an infrared image furnace, isooctane is used as the reformed fuel, a space velocity of 25000 h −1 , steam / carbon = 2, and oxide / carbon = 0. The reforming property test was conducted under the condition of .1. Further, as the temperature condition, the outlet temperature is set to 550 ° C., the measurement items are the outlet gas components (H 2 , CO, CO 2 , N 2 , CH 4 , HC, H 2 O), and the outlet gas of each component Based on the concentration, the conversion was calculated by the following formula. The resulting conversion is shown in FIG. FIG. 11 shows the H 2 concentration and CH 4 concentration in the outlet gas.
Conversion (%) = (carbon in CO, CO 2 and CH 4 ) / (carbon in isooctane)
As is clear from the results shown in FIGS. 10 and 11, in the catalyst for hydrogen generation reaction of the present invention obtained using the catalyst support obtained by the methods described in Examples 2 to 5 and Comparative Examples 3 to 8, A high conversion rate of 92% or more and a high hydrogen concentration of 40% by mass or more were achieved at the same time, and it was confirmed that they had very excellent reforming characteristics.
＜付着性試験＞
実施例５及び比較例９に記載の方法で前記金属プレート、前記コージエライトプレート及びＳｉＣプレート上にそれぞれ形成せしめた金属酸化物被覆（膜厚：約５μｍ）について、以下のようにして付着性を評価した。すなわち、表面に金属酸化物被覆を形成した各基板を超音波洗浄器にかけて３０分間×４回超音波振動を与え、その間における薄膜の残存割合（重量基準）を測定した。
<Adhesion test>
About the metal oxide coating (film thickness: about 5 μm) formed on the metal plate, the cordierite plate, and the SiC plate by the method described in Example 5 and Comparative Example 9, the adhesion was as follows. Evaluated. That is, each substrate having a metal oxide coating on the surface was subjected to ultrasonic vibration for 30 minutes × 4 times by applying an ultrasonic cleaner, and the remaining ratio (weight basis) of the thin film was measured.
得られた結果を図１２（実施例５）及び図１３（比較例９）に示す。図１２及び図１３に示した結果から明らかな通り、コロイド溶液を高剪断速度の下で混合した後に基材に塗布して高速で乾燥及び焼成して得た本発明の水素生成反応用触媒担体においては、各種基材に対する付着性が大幅に向上していることが確認された。 The obtained results are shown in FIG. 12 (Example 5) and FIG. 13 (Comparative Example 9). As is clear from the results shown in FIGS. 12 and 13, the catalyst carrier for the hydrogen generation reaction of the present invention obtained by mixing the colloidal solution at a high shear rate, applying the colloidal solution to the substrate, drying and firing at high speed, and the like. In, it was confirmed that the adhesion to various substrates was greatly improved.
また、実施例６〜８及び比較例１０に記載の方法で前記金属プレート上に形成せしめた金属酸化物被覆についてもそれぞれ、上記と同様にして付着性を評価した。得られた結果（２時間後の残存割合（重量基準））を表１５に示す。 In addition, the adhesion of the metal oxide coatings formed on the metal plate by the methods described in Examples 6 to 8 and Comparative Example 10 was evaluated in the same manner as described above. The obtained results (residual ratio after 2 hours (weight basis)) are shown in Table 15.
表１５に示した結果から明らかな通り、原料流体組成物を混合する際の剪断速度が増加するにしたがって得られた金属酸化物薄膜における基材に対する付着性が向上し、特に剪断速度が１００００ｓｅｃ−１以上になると付着性が顕著に向上することが確認された。 As apparent from the results shown in Table 15, as the shear rate when mixing the raw material fluid composition increases, the adhesion of the obtained metal oxide thin film to the substrate is improved, and in particular, the shear rate is 10,000 sec − It was confirmed that when it was 1 or more, the adhesion was remarkably improved.
＜ナノ細孔の評価＞
実施例１に記載の方法で得られた金属酸化物薄膜及び実施例９に記載の方法で得られた金属酸化物粉末について、以下のようにして窒素吸着法並びにＸ線小角散乱法によりナノ細孔を有することを確認した。
<Evaluation of nanopore>
The metal oxide thin film obtained by the method described in Example 1 and the metal oxide powder obtained by the method described in Example 9 were nano-sized by the nitrogen adsorption method and the X-ray small angle scattering method as follows. It confirmed that it had a hole.
すなわち、窒素吸着法は、ある平衡蒸気圧にて固体表面に吸着されたガス量又は固体表面から脱離されたガス量を静的容積法によって測定する手法である。吸着質の臨界温度で一定温度に保持された固体試料の入ったサンプルセルに既知量の吸着ガスを導入するか、或いはサンプルセルから既知量の吸着ガスを除去することにより等温線データが得られる。平衡圧力にて吸着又は脱離されるガスの量は、導入又は除去されたガス量と試料周辺の空隙部を満たすのに必要なガス量との差に相当する。本測定では、ＱＵＡＮＴＡＣＨＲＯＭＥ社製全自動ガス吸着量測定装置（オートソーブ１ＭＰ／ＬＰ）を用いた。そして、０．０５〜０．１５ｇの試料を用い、測定温度−１９６℃、大気圧との相対圧力Ｐ／Ｐ０が０．００００１〜１の範囲で窒素吸着測定を、その後継続してＰ／Ｐ０が０．０１〜１の範囲で窒素の脱離測定を行った。窒素ガスの吸着量をプロットすることにより吸着等温線を得ることができ、ＢＪＨ法と呼ばれる解析法により、細孔径分布を求めた。なお、ＢＪＨ法とは、メソ細孔分布計算に最も有効なモデルであり、孔は全て円筒形であると仮定したモデルである。実施例１に記載の方法で得られた金属酸化物多孔体の測定結果を図１４に示す。 That is, the nitrogen adsorption method is a method of measuring the amount of gas adsorbed on the solid surface at a certain equilibrium vapor pressure or the amount of gas desorbed from the solid surface by the static volume method. Isotherm data can be obtained by introducing a known amount of adsorbed gas into a sample cell containing a solid sample held at a constant temperature at the adsorbate's critical temperature, or by removing a known amount of adsorbed gas from the sample cell. . The amount of gas adsorbed or desorbed at the equilibrium pressure corresponds to the difference between the amount of gas introduced or removed and the amount of gas necessary to fill the void around the sample. In this measurement, a fully automatic gas adsorption amount measuring device (autosorb 1MP / LP) manufactured by QUANTACHROME was used. Then, using a sample of 0.05 to 0.15 g, the nitrogen adsorption measurement is continued in the range where the measurement temperature is −196 ° C. and the relative pressure P / P 0 to the atmospheric pressure is 0.00001 to 1, and then P / Nitrogen desorption measurement was performed in the range of P 0 from 0.01 to 1. An adsorption isotherm can be obtained by plotting the adsorption amount of nitrogen gas, and the pore size distribution was obtained by an analysis method called a BJH method. The BJH method is the most effective model for calculating the mesopore distribution, and is a model assuming that all the holes are cylindrical. The measurement result of the metal oxide porous body obtained by the method described in Example 1 is shown in FIG.
また、Ｘ線小角散乱法には平行性とエネルギー密度に優れた放射光施設におけるアンジュレータービームラインのＸ線を用いた。Ｘ線エネルギーを１０ｋｅＶ（波長０．１２４ｎｍ）に設定し、まず四象限スリットを用いて０．０４ｍｍ□程度にＸ線ビームを絞り、小角散乱法のビームの起点とする。その起点から約６５ｃｍ下流のところに直径０．５ｍｍのピンホールを置いて余分な散乱光を遮るとともにそのすぐ下流に密着させて試料を設置した。Ｘ線の試料透過後の強度が１／ｅ（ｅは自然対数の底）になるように吸収量を計算して試料の適正厚みを算出し、それに従って試料の圧粉体を作製した。試料から正確に５０ｃｍ下流（起点から１１５ｃｍ下流）側にイメージングプレートを設置して散乱Ｘ線を記録した。透過Ｘ線の位置にはカバーガラスを重ねたアッテネーターを設置してイメージングプレートの損傷を防ぐとともに適当な強度で透過Ｘ線の位置がイメージングプレートに記録されるようにした。解析にあたっては、イメージングプレート上の透過Ｘ線位置を中心とした同心円上に記録されたＸ線強度の平均値を求め、同心円の半径を角度に換算して散乱角度対強度のグラフを描いた。試料内に球状の散乱体を仮定して散乱体半径の分布を適度に変化させ、前記散乱角度対強度のグラフを説明できる適当な分布を求めた。実施例９に記載の方法で得られた金属酸化物多孔体の測定結果を図１５に示す。また、比較のため、バルク体である銅箔（厚さ６μｍ）及びアルミニウム箔（厚さ１００μｍ）についての測定結果も図１５に示す。 In addition, the X-ray small angle scattering method used X-rays of an undulator beam line in a synchrotron radiation facility excellent in parallelism and energy density. The X-ray energy is set to 10 keV (wavelength 0.124 nm), and the X-ray beam is first narrowed down to about 0.04 mm □ using a four-quadrant slit to be the starting point of the small-angle scattering method beam. A pinhole having a diameter of 0.5 mm was placed about 65 cm downstream from the starting point to block excess scattered light, and the sample was placed in close contact with the pinhole. The amount of absorption was calculated so that the intensity of the X-ray after passing through the sample was 1 / e (e is the base of the natural logarithm), the appropriate thickness of the sample was calculated, and the green compact of the sample was prepared accordingly. An X-ray was recorded by setting an imaging plate on the exact 50 cm downstream side (115 cm downstream from the starting point) from the sample. An attenuator overlaid with a cover glass was installed at the position of the transmitted X-ray to prevent the imaging plate from being damaged, and the position of the transmitted X-ray was recorded on the imaging plate with an appropriate intensity. In the analysis, an average value of X-ray intensities recorded on a concentric circle centered on a transmission X-ray position on the imaging plate was obtained, and a graph of scattering angle versus intensity was drawn by converting the radius of the concentric circle into an angle. Assuming a spherical scatterer in the sample, the distribution of the scatterer radius was appropriately changed, and an appropriate distribution capable of explaining the graph of the scattering angle versus the intensity was obtained. The measurement result of the metal oxide porous body obtained by the method described in Example 9 is shown in FIG. For comparison, FIG. 15 also shows the measurement results for a copper foil (thickness 6 μm) and an aluminum foil (thickness 100 μm), which are bulk bodies.
これらの図面、特に図１５に示した結果から明らかな通り、本発明の方法により得られた本発明の金属酸化物多孔体には、直径が２ｎｍ以下という非常に微細なナノ細孔が形成されていることが確認された。 As is clear from these drawings, particularly the results shown in FIG. 15, in the metal oxide porous material of the present invention obtained by the method of the present invention, very fine nanopores having a diameter of 2 nm or less are formed. It was confirmed that
以上説明したように、本発明においては、金属酸化物のコロイド溶液や金属塩の溶液を高剪断速度の下で混合し、実質的に共沈させることなく熱処理するようにすることにより、驚くべきことに得られる金属酸化物は直径が１０ｎｍ以下のナノ細孔を有し且つナノ細孔を構成する壁体において金属酸化物が均質に分散している従来にない新規なものとなり、各種基材に対する付着性及び耐熱性が向上し、更に薄膜化も可能となる。そして、本発明においては、かかる金属酸化物ナノ多孔体を構成する成分をジルコニア及びセリアを特定量含有するジルコニア／セリア２成分系又はジルコニア、セリア及びアルミナを特定量含有するジルコニア／セリア／アルミナ３成分系とすることによって水素生成反応における改質特性が非常に優れた水素生成反応用触媒が得られるようになる。 As described above, in the present invention, a colloidal solution of metal oxide or a solution of metal salt is mixed at a high shear rate and is heat-treated without substantial coprecipitation. In particular, the resulting metal oxide has nanopores having a diameter of 10 nm or less and is a novel and unprecedented metal oxide that is uniformly dispersed in the wall constituting the nanopore. Adhesiveness and heat resistance to the film are improved, and further thinning is possible. In the present invention, the component constituting the metal oxide nanoporous material is a zirconia / ceria two-component system containing a specific amount of zirconia and ceria, or zirconia / ceria / alumina 3 containing a specific amount of zirconia, ceria and alumina. By using the component system, a hydrogen generation reaction catalyst having very excellent reforming characteristics in the hydrogen generation reaction can be obtained.
したがって、本発明は、燃料電池等の分離膜電池システムにおいて燃料となる水素を生成させるための水素生成反応用触媒を得るために非常に有用な技術である。 Therefore, the present invention is a very useful technique for obtaining a hydrogen generation reaction catalyst for generating hydrogen as a fuel in a separation membrane cell system such as a fuel cell.
Claims (9)
前記被覆におけるセリアの含有量が１０〜６０質量％、ジルコニアの含有量が２０〜９０質量％、アルミナの含有量が７０質量％以下であり、
前記被覆に１０ａｔ％以上含有されるすべての金属酸化物の金属元素について、加速電圧１５ｋＶ、電子ビーム径１μｍのＸ線マイクロアナライザーを用いて０．５ｍｍ以上の範囲を任意に線分析して求めた下記式（２）：
Ｋ値（％）＝（被覆から検出されたＸ線強度）／（純物質から得られるＸ線強度）
で表されるＫ値が、前記金属元素のすべてについて、全測定点のうちの６５％以上の測定点において下記式（３）：
で表される条件を満たしていることを特徴とする燃料改質用触媒担体。 A catalyst carrier comprising a substrate and the covered bets that is composed of two or more metal oxide formed on the surface of the substrate,
The ceria content in the coating is 10 to 60% by mass, the zirconia content is 20 to 90% by mass, and the alumina content is 70% by mass or less.
The metal elements of all the metal oxides contained in the coating in an amount of 10 at% or more were obtained by arbitrarily performing a line analysis over a range of 0.5 mm or more using an X-ray microanalyzer having an acceleration voltage of 15 kV and an electron beam diameter of 1 μm. Following formula (2):
K value (%) = (X-ray intensity detected from coating) / (X-ray intensity obtained from pure substance)
The K value represented by the following formula (3) for all the metal elements at the measurement points of 65% or more of all the measurement points:
A catalyst carrier for fuel reforming characterized by satisfying the condition represented by:
Ｈ（Ｌ）≦２０ｎｍ （４）
［式（４）中、Ｈ（Ｌ）は各測定点（走査距離＝Ｌ）における高さ像（ｎｍ）を示す。但し、全測定点における高さ像Ｈの平均値を零とする。］
で表される条件を満たしており、且つ、下記式（５）及び（６）：
により求めた二次微係数Ｈ”（Ｌ）が、全測定点のうちの６０％以下の測定点において下記式（７）：
−０．０５ｎｍ−１≦Ｈ”（Ｌ）≦０．０５ｎｍ−１ （７）
で表される条件を満たしていることを特徴とする請求項１〜６のうちのいずれか一項に記載の触媒担体。 Using a tip having a curvature radius of 5 nm with a scanning probe microscope, the height image of the surface of the coating is arbitrarily measured in a tapping mode at intervals of 3 nm or more and less than 4 nm, and the scanning distance L is 2 μm or more in total. The height image H (L) obtained as a function is represented by the following formula (4) at 80% or more of the measurement points.
H (L) ≦ 20nm (4)
[In Expression (4), H (L) represents a height image (nm) at each measurement point (scanning distance = L). However, the average value of the height image H at all measurement points is set to zero. ]
And the following formulas (5) and (6):
The second differential coefficient H ″ (L) obtained by the following equation (7) at the measurement points of 60% or less of all the measurement points:
−0.05 nm −1 ≦ H ″ (L) ≦ 0.05 nm −1 (7)
The catalyst carrier according to any one of claims 1 to 6 , wherein a condition represented by the following is satisfied.
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