JP2004321986A - Exhaust gas purification catalyst - Google Patents
Exhaust gas purification catalyst Download PDFInfo
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- JP2004321986A JP2004321986A JP2003121983A JP2003121983A JP2004321986A JP 2004321986 A JP2004321986 A JP 2004321986A JP 2003121983 A JP2003121983 A JP 2003121983A JP 2003121983 A JP2003121983 A JP 2003121983A JP 2004321986 A JP2004321986 A JP 2004321986A
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- exhaust gas
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- 239000003054 catalyst Substances 0.000 title claims abstract description 50
- 238000000746 purification Methods 0.000 title claims abstract description 30
- 239000002131 composite material Substances 0.000 claims abstract description 27
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 23
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 23
- 229910052751 metal Inorganic materials 0.000 claims abstract description 15
- 239000002184 metal Substances 0.000 claims abstract description 14
- 229910052742 iron Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 6
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 6
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 6
- 229910052779 Neodymium Inorganic materials 0.000 claims abstract description 5
- 229910052772 Samarium Inorganic materials 0.000 claims abstract description 5
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 5
- 150000002739 metals Chemical class 0.000 claims description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract description 7
- 229910052717 sulfur Inorganic materials 0.000 abstract description 7
- 239000011593 sulfur Substances 0.000 abstract description 7
- 231100000572 poisoning Toxicity 0.000 abstract description 5
- 230000000607 poisoning effect Effects 0.000 abstract description 5
- 239000007789 gas Substances 0.000 description 39
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 21
- 229910000510 noble metal Inorganic materials 0.000 description 13
- 238000002485 combustion reaction Methods 0.000 description 12
- 239000000446 fuel Substances 0.000 description 12
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- 229910002091 carbon monoxide Inorganic materials 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 239000011572 manganese Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000006722 reduction reaction Methods 0.000 description 5
- 239000010948 rhodium Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- RTHYXYOJKHGZJT-UHFFFAOYSA-N rubidium nitrate Inorganic materials [Rb+].[O-][N+]([O-])=O RTHYXYOJKHGZJT-UHFFFAOYSA-N 0.000 description 3
- KHAUBYTYGDOYRU-IRXASZMISA-N trospectomycin Chemical compound CN[C@H]([C@H]1O2)[C@@H](O)[C@@H](NC)[C@H](O)[C@H]1O[C@H]1[C@]2(O)C(=O)C[C@@H](CCCC)O1 KHAUBYTYGDOYRU-IRXASZMISA-N 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- 101100258086 Postia placenta (strain ATCC 44394 / Madison 698-R) STS-01 gene Proteins 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 2
- 150000002736 metal compounds Chemical class 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- CFYGEIAZMVFFDE-UHFFFAOYSA-N neodymium(3+);trinitrate Chemical compound [Nd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CFYGEIAZMVFFDE-UHFFFAOYSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 159000000021 acetate salts Chemical class 0.000 description 1
- 229910052936 alkali metal sulfate Inorganic materials 0.000 description 1
- -1 alkaline earth metal carbonate Chemical class 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 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 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910001960 metal nitrate Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000010944 silver (metal) Substances 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
Images
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、自動車用エンジン等の内燃機関から排出される排気ガスを浄化するための排気ガス浄化触媒に関し、詳細には、排ガス中に含まれるＮＯｘの浄化性能が著しく改良された排気ガス浄化触媒に関する。
【０００２】
【従来の技術】
一般に、自動車用エンジン等の内燃機関から排出される排気ガス中には、炭化水素系化合物（以下「ＨＣ」という。）、一酸化炭素（ＣＯ）、窒素酸化物（ＮＯｘ）等の物質（エミッション）が含まれている。これらの物質の排出量を減らすために、エンジンの空燃比等の、燃焼条件の最適化の他、排気ガス中に含まれる物質を排気ガス浄化触媒によって除去する方法が一般的に用いられている。
【０００３】
この排気ガス浄化触媒としては、アルミナ等の多孔質金属酸化物担体に、白金（Ｐｔ）、ロジウム（Ｒｈ）、パラジウム（Ｐｄ）等の貴金属を担持した、いわゆる三元触媒が一般的である。この三元触媒は、ＣＯ及びＨＣを酸化するとともに、ＮＯｘをＮ２に還元する能力を有することが知られている。
【０００４】
近年、自動車エンジン等の内燃機関においては、Ｏ２センサーを使用して空燃比データをフィードバックすることによって、空燃比は理論空燃比に高精度で制御されているため、通常の運転条件下では、排気ガスの浄化は三元触媒によって十分に行うことができる。
【０００５】
しかし、自動車の加速域等、運転条件が大きく変化する条件下では、上記の空燃比制御が完全でなく、一時的な空気過剰（リーン）及び燃料過剰（リッチ）になる。三元触媒は、理論空燃比近傍で内燃機関を運転した場合に排出される排気ガス中のＨＣ、ＣＯ、及びＮＯｘを効率よく浄化することができる。しかし、内燃機関に供給される混合気中の燃料と空気の割合が理論空燃比から外れた場合には、三元触媒は、充分な排気ガス浄化能力を発揮できない。
【０００６】
そこで、排気ガス中の酸素濃度が高い時には酸素を吸蔵し、酸素濃度が低い時には酸素を放出する能力（ＯＳＣ能）を有する金属酸化物、例えばＣｅＯ２又はＣｅＯ２−ＺｒＯ２複合酸化物などを排気ガス浄化触媒の助触媒として用い、排気ガス中の酸素濃度を調節し、三元触媒の排気ガス浄化能力を充分発揮できる方法が使用されている。しかし、ＣｅＯ２及びＣｅＯ２−ＺｒＯ２複合酸化物等の単体は、ＯＳＣ能を高温でしか発現できず、排気ガス浄化触媒として用いるためには、ＣｅＯ２等にＰｔ等の貴金属を担持してＯＳＣ能を発現できる温度を低くする必要があった。また、ＯＳＣ能を有する、貴金属を担持したＣｅＯ２等を用いても、酸素濃度の調節は完全ではなく、排気ガス中に含まれるＮＯｘを完全に除去することはできない。
【０００７】
排気ガス中に含まれるＮＯｘについては、三元触媒のＮＯｘ浄化能力を補うための吸蔵還元型ＮＯｘ浄化触媒が知られている（例えば、特許文献１参照）。これは、内燃機関において、酸素過剰の燃焼条件下で排気ガス中のＮＯｘ濃度が高い場合には一時的にＮＯｘを吸蔵し、一方、燃料過剰の燃焼条件下、排気ガス中のＮＯｘ濃度が低く、かつＨＣ及びＣＯ等が多い還元性雰囲気になるとＮＯｘを放出し（ＮＯｘ吸蔵放出能）、Ｐｔ等の排気ガス浄化触媒の作用によりＮＯｘを還元浄化する触媒である。この吸蔵還元型ＮＯｘ浄化用触媒のＮＯｘ吸蔵材としては、アルカリ金属又はアルカリ土類金属が使用され、Ｐｔ等の触媒成分とアルカリ金属又はアルカリ土類金属の炭酸塩や酢酸塩をγ−アルミナ等の担体に担持して排気ガス浄化触媒が構成されている。
【０００８】
一方、特定のペロブスカイト型複合酸化物はＮＯｘをＮ２とＯ２に分解する作用を有することが知られており、特定のペロブスカイト型複合酸化物を担体に担持したＮＯｘ接触還元触媒が知られている（例えば、特許文献２参照）。
【０００９】
しかしながら、炭酸塩や酢酸塩を用いてアルカリ金属又はアルカリ土類金属を坦持した吸蔵還元型ＮＯｘ浄化用触媒では、約５００℃を上回る触媒温度におけるＮＯｘ浄化性能を高める必要があった。また、従来のペロブスカイト型複合酸化物を含む触媒は、自動車用エンジン等の内燃機関から排出される排気ガスの浄化に使用するためには、ＮＯｘ浄化率を高める必要があった。
【００１０】
そこで、約５００℃を上回る触媒温度でも優れたＮＯｘ浄化性能を発揮することができる、改良された排気ガス浄化触媒が提案された。この触媒は、少なくとも２種の金属元素を含むペロブスカイト型複合酸化物に、Ｐｔ、Ｐｄ、Ｒｈ、Ａｕ、Ａｇ、及びＩｒの少なくとも１種の触媒成分が担持されたことを特徴とするものであり、好ましいペロブスカイト型複合酸化物として、Ｌａ１−ｘＫｘＢＯ３（Ｂは、Ｍｎ、Ｃｏ、Ｆｅ、及びＮｉの少なくとも１種）の構造式又はＡ１−ｘＫｘＢ１−ｙＴｉｙＯ３（Ａは、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、及びＹの少なくとも１種、Ｂは、Ｍｎ、Ｃｏ、Ｆｅ、及びＮｉの少なくとも１種）の構造式を有するＫを含む特定のペロブスカイト型複合酸化物が例示されている（例えば、特許文献３参照）。
【００１１】
【特許文献１】
特開平９−２４８４５８号公報
【特許文献２】
特開平５−２６１２８９号公報
【特許文献３】
特開２００１−２６９５７８号公報
【００１２】
【発明が解決しようとする課題】
しかしながら、上記ペロブスカイト型複合酸化物に貴金属を担持させた排気ガス浄化触媒では、高温ＮＯｘ浄化性能は向上したが、低温におけるリーン雰囲気のＮＯｘを十分に浄化することができないという問題がある。さらに、吸蔵還元型ＮＯｘ浄化触媒中のアルカリ金属は、燃料中に含まれる硫黄により安定な硫酸塩を形成する、いわゆる硫黄被毒によって性能が低下するという問題もある。
【００１３】
従って、本発明は、高温のみならず低温においても高いＮＯｘ浄化性能を示し、かつ耐硫黄被毒性の高い吸蔵還元型ＮＯｘ浄化触媒を提供することを目的とする。
【００１４】
【課題を解決するための手段】
上記目的を達成するために本発明によれば、下式
Ａ１−ｘＲｂｘＭ１−ｙ−ｚＴｉｙＲｚＯ３
（式中、ＡはＬａ、Ｎｄ及びＳｍからなる群より選ばれる１種以上の金属を表し、ＭはＭｎ、Ｆｅ、Ｃｏ及びＮｉからなる群から選ばれる１種以上の金属を表し、ＲはＰｔ、Ｐｄ及びＲｈからなる群から選ばれる１種以上の金属を表し、ｘは０．１＜ｘ＜１を満たす数字を表し、ｙは０＜ｙ＜１を満たす数字を表し、ｚは０＜ｚ＜１を満たす数字を表し、但しｙ＞ｚであり、０＜ｙ＋ｚ＜０．５である）
で表されるペロブスカイト型複合金属酸化物からなる排気ガス浄化触媒が提供される。このペロブスカイト型複合金属酸化物は担体上に担持されていてもよい。
【００１５】
【発明の実施の形態】
従来のペロブスカイト型複合金属酸化物を含む排気ガス浄化触媒は、ペロブスカイト型複合金属酸化物にＰｔ等の貴金属を担持させることにより構成されている。これに対して、本発明の排気ガス浄化触媒は、ペロブスカイト型複合金属酸化物を構成する金属の一部を貴金属で置換し、この複合酸化物の結晶格子中に貴金属を配置したことを特徴とする。
【００１６】
すなわち、本発明の排気ガス浄化触媒は下式
Ａ１−ｘＲｂｘＭ１−ｙ−ｚＴｉｙＲｚＯ３
の構造を有するペロブスカイト型複合金属酸化物から構成される。上式中、ＡはＬａ、Ｎｄ及びＳｍからなる群より選ばれる１種以上の金属を表し、Ｎｄであることが好ましく、ＭはＭｎ、Ｆｅ、Ｃｏ及びＮｉからなる群から選ばれる１種以上の金属を表し、Ｍｎであることが好ましく、ＲはＰｔ、Ｐｄ及びＲｈからなる群から選ばれる１種以上の金属を表し、Ｐｔであることが好ましい。式中、ｘは０．１＜ｘ＜１を満たす数字を表し、０．３であることが好ましく、ｙは０＜ｙ＜１を満たす数字を表し、０．２５であることが好ましく、ｚは０＜ｚ＜１を満たす数字を表し、０．０５であることが好ましく、但しｙ＞ｚであり、０＜ｙ＋ｚ＜０．５である。特に好ましいペロブスカイト型複合金属酸化物は、Ｎｄ０．７Ｒｂ０．３Ｎｎ０．７Ｔｉ０．２５Ｐｔ０．０５Ｏ３である。
【００１７】
本発明の排気ガス浄化触媒は、ペロブスカイト型複合金属酸化物の結晶格子中に貴金属を有するため、従来のようにペロブスカイト型複合金属酸化物に貴金属を担持させた場合と比較して、貴金属の分散性が向上しており、その結果、従来の触媒では十分に浄化することができなかった高温域（５００℃以上）でのＮＯｘ浄化性能と、低温域（４００℃以下）でのＮＯｘ浄化性能を大幅に向上することができる。さらに、貴金属の分散性が高いため、硫黄被毒によって形成したアルカリ金属の硫酸塩と貴金属との接触性が従来の触媒と比較して向上し、その結果、硫酸塩の分解が促進され、硫黄流通後もＮＯｘ浄化性能を維持することができ、耐硫黄被毒性が向上する。
【００１８】
この貴金属を有するペロブスカイト型複合金属酸化物は、その金属酸化物を構成する金属の比を有するように、金属の硝酸塩、酢酸塩、及び塩化物、並びに金属酸化物ゾル等から選ばれる金属化合物を混合した後、又はこれらの金属化合物を水溶液又は懸濁液にして混合・乾燥した後、空気中で４００〜１０００℃に加熱することによって製造することができる。
【００１９】
本発明において、このペロブスカイト型複合金属酸化物を担体に担持させてもよい。担体としては、従来より排気ガス浄化触媒用担体として用いられてきた担体を用いることができ、ハニカム構造を有する多孔質モノリス担体が好ましく、特にコージェライト製ハニカムを用いることが好ましい。
【００２０】
担体上へのこの金属酸化物の担持は、公知の方法、例えばこの金属酸化物及び金属酸化物ゾルを含むスラリーを担体上にコートして焼成するなどの方法によって行うことができる。担体上への金属酸化物の担持量は、任意に決定できるが、アルミナ：ペロブスカイト型複合金属酸化物＝１０：１であることが好ましい。
【００２１】
本発明の排ガス浄化用触媒は、適当なユニット中に配置する等の公知の方法によって、自動車用エンジン等の内燃機関から排出される排気ガス流路中に配置し、排気ガス中のＮＯｘ等の成分を浄化するための触媒として用いることができる。
【００２２】
以下、本発明の排気ガス浄化触媒を、実施例に基づき、さらに具体的に説明するが、本発明はこれらに限定されるものではない。
【００２３】
【実施例】
実施例１
５２．２８ｇの硝酸ネオジム、７．５４ｇの硝酸ルビジウム、３４．２３ｇの硝酸マンガン、１１．３４ｇのチタニアゾル（石原産業製ＳＴＳ−０１、固形分３０ｗｔ％）、３７．７７ｇのジニトロジアミンＰｔ硝酸水溶液（キャタラー製８Ｐ、Ｐｔ４．４ｗｔ％）を５００ｍＬのイオン交換水に加え、室温で１時間攪拌した。次いで１２０℃で攪拌を続け、粘性があらわれてきたらルツボに移し、１２０℃で２時間脱水させた。次にルツボごと炉に入れ、２００℃で５時間、４８０℃で２時間仮焼し、さらに９００℃で１０時間焼成して、Ｎｄ０．７Ｒｂ０．３Ｍｎ０．７Ｔｉ０．２５Ｐｔ０．０５Ｏ３の組成を有するペロブスカイト型複合酸化物粉末を得た。得られた粉末を乳鉢で十分に粉砕し、１ｔｏｎの静水圧を加えて固めたものをフルイの上で粉砕し、直径０．５〜１ｍｍの大きさのペレット粒子を得た。
【００２４】
比較例１
５３．９７ｇの硝酸ネオジム、７．７８ｇの硝酸ルビジウム、３５．３４ｇの硝酸マンガン、１４．０５ｇのチタニアゾル（石原産業製ＳＴＳ−０１、固形分３０ｗｔ％）を５００ｍＬのイオン交換水に加え、室温で１時間攪拌した。次いで１２０℃で攪拌を続け、粘性があらわれてきたらルツボに移し、１２０℃で２時間脱水させた。次にルツボごと炉に入れ、２００℃で５時間、４８０℃で２時間仮焼し、さらに９００℃で１０時間焼成して、Ｎｄ０．７Ｒｂ０．３Ｍｎ０．７Ｔｉ０．３Ｏ３の組成を有するペロブスカイト型複合酸化物粉末を得た。得られた粉末４０ｇを乳鉢で十分に粉砕し、イオン交換水中に入れ、３８．９９ｇのジニトロジアミンＰｔ硝酸水溶液（キャタラー製８Ｐ、Ｐｔ４．４ｗｔ％）を加え、１時間攪拌後、１２０℃で２時間脱水させ、５００℃で２時間焼成し、Ｐｔ＝１１．５８ｇ／Ｎｄ０．７Ｒｂ０．３Ｍｎ０．７Ｔｉ０．３Ｏ３＝２７０ｇを得た。得られた粉末を実施例１と同様にしてペレット化した。
【００２５】
比較例２
２５ｇのアルミナ、４．２１ｇのジニトロジアミンＰｔ硝酸水溶液（キャタラー製８Ｐ、Ｐｔ４．４ｗｔ％）を２００ｍＬのイオン交換水に加え、室温で１時間攪拌した。次いで１２０℃で２時間脱水させ、５００℃で２時間焼成した。得られた粉末２５ｇと４．７８ｇの硝酸ルビジウムを２００ｍＬのイオン交換水に加え、１時間攪拌後、１２０℃で２時間脱水させ、５００℃で２時間焼成し、Ｒｂ＝０．３５ｍｏｌ／Ｐｔ＝１１．５８ｇ／Ａｌ２Ｏ３＝２７０ｇの粉末を得た。得られた粉末を実施例１と同様にしてペレット化した。
【００２６】
ＮＯｘ浄化性能の評価
上記のペレット２ｇを固定床流通式反応器（ガス流量：６．６Ｌ／ｍｉｎ）に充填し、下記条件で試験を行った。
初期性能
リーン組成：ＮＯ＝５００ｐｐｍ、Ｃ３Ｈ６＝６６７ｐｐｍ、ＣＯ＝０．１％、Ｏ２＝６．５％、ＣＯ２＝１０％、Ｈ２Ｏ＝２％、Ｎ２＝バランス。
リッチ組成：ＮＯ＝５００ｐｐｍ、Ｃ３Ｈ６＝６６７ｐｐｍ、ＣＯ＝０．６％、Ｏ２＝０．４％、ＣＯ２＝１０％、Ｈ２Ｏ＝２％、Ｎ２＝バランス。
６００℃リッチ処理１０分後、６００、５００、４００、３００、７００℃でリーン／リッチ＝２／２分繰り返した。リーン２分後の出ＮＯ濃度（ｐｐｍ）を測定し、ＮＯ浄化率とした。ＮＯ浄化率（％）＝（入りＮＯ濃度（５００ｐｐｍ）−出ＮＯ濃度（ｐｐｍ））×１００／（入りＮＯ濃度（５００ｐｐｍ）である。
【００２７】
耐久後性能
４００℃硫黄耐久試験（リーン、リッチ組成にそれぞれＳＯ２を１００ｐｐｍ混入したものを４／１分切り替え、４時間耐久した）後のサンプルを初期性能と同じ方法で評価した。
【００２８】
以上の結果を図１及び図２に示す。この結果より、本発明の排気ガス浄化触媒は６００℃以上の高温域においてＮＯｘ浄化能が大幅に改善され、低温域においても性能が低下しない（図１）。さらに、硫黄被毒劣化も低減されている（図２）。
【００２９】
【発明の効果】
本発明の排気ガス浄化触媒は、高温のみならず低温においても高いＮＯｘ浄化性能を示し、かつ耐硫黄被毒性の高い、自動車エンジンの内燃機関から放出される排気ガス中のエミッションを低減することができ、特にＮＯｘを浄化する能力に優れている。
【図面の簡単な説明】
【図１】触媒の初期ＮＯｘ浄化性能を示すグラフである。
【図２】触媒の耐硫黄被毒性を示すグラフである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purifying catalyst for purifying exhaust gas discharged from an internal combustion engine such as automobile engine, in particular, the exhaust gas purification purification performance of the NO x contained in the exhaust gas is significantly improved Regarding the catalyst.
[0002]
[Prior art]
Generally, substances such as hydrocarbon compounds (hereinafter, referred to as “HC”), carbon monoxide (CO), and nitrogen oxides (NO x ) are contained in exhaust gas discharged from an internal combustion engine such as an automobile engine. Emissions) are included. In order to reduce the emission of these substances, in addition to optimizing combustion conditions such as the air-fuel ratio of an engine, a method of removing substances contained in exhaust gas by an exhaust gas purification catalyst is generally used. .
[0003]
As this exhaust gas purifying catalyst, a so-called three-way catalyst in which a noble metal such as platinum (Pt), rhodium (Rh), and palladium (Pd) is supported on a porous metal oxide carrier such as alumina is generally used. This three-way catalyst is known to have the ability to oxidize CO and HC and reduce NO x to N 2 .
[0004]
In recent years, in an internal combustion engine such as an automobile engine, the air-fuel ratio is controlled to the stoichiometric air-fuel ratio with high accuracy by feeding back the air-fuel ratio data using an O 2 sensor. Purification of exhaust gas can be sufficiently performed by a three-way catalyst.
[0005]
However, under conditions where driving conditions change significantly, such as in the acceleration region of an automobile, the above-described air-fuel ratio control is not perfect, resulting in a temporary excess of air (lean) and an excess of fuel (rich). Three-way catalyst can purify the stoichiometric air-fuel ratio HC in exhaust gas discharged when the internal combustion engine is operated in the vicinity, CO, and NO x efficiently. However, when the ratio of fuel and air in the air-fuel mixture supplied to the internal combustion engine deviates from the stoichiometric air-fuel ratio, the three-way catalyst cannot exhibit sufficient exhaust gas purification ability.
[0006]
Therefore, a metal oxide having the ability to occlude oxygen when the oxygen concentration in the exhaust gas is high and release oxygen when the oxygen concentration is low (OSC capability), such as CeO 2 or CeO 2 —ZrO 2 composite oxide, is used. A method has been used which is used as a promoter of an exhaust gas purifying catalyst, adjusts the oxygen concentration in the exhaust gas, and can sufficiently exhibit the exhaust gas purifying ability of a three-way catalyst. However, simple substances such as CeO 2 and CeO 2 —ZrO 2 composite oxides can only exhibit OSC capability at high temperatures, and in order to be used as an exhaust gas purifying catalyst, a noble metal such as Pt is supported on CeO 2 or the like. It was necessary to lower the temperature at which the OSC capability could be exhibited. In addition, even if CeO 2 or the like having a noble metal and having OSC capability is used, the adjustment of the oxygen concentration is not perfect, and it is not possible to completely remove NO x contained in the exhaust gas.
[0007]
The NO x contained in the exhaust gas, storage reduction the NO x purification catalyst to compensate for the NO x purification ability of the three-way catalyst has been known (e.g., see Patent Document 1). This is an internal combustion engine, an oxygen excess of when the concentration of NO x in the exhaust gas at a high combustion conditions occluded temporarily NO x, whereas, excess fuel combustion conditions, NO x in the exhaust gas concentration is low, and the HC and CO etc. becomes large a reducing atmosphere to release NO x (NO x storage-and-release ability) is a catalyst that reduces and purifies NO x by the action of the exhaust gas purifying catalyst such as Pt. An alkali metal or an alkaline earth metal is used as a NO x storage material of the storage reduction type NO x purification catalyst, and a catalyst component such as Pt and an alkali metal or alkaline earth metal carbonate or acetate are converted to γ- An exhaust gas purifying catalyst is supported on a carrier such as alumina.
[0008]
On the other hand, certain of the perovskite-type composite oxide is known to have an action of decomposing the NO x to N 2 and O 2, is a specific perovskite type composite oxide was supported on a carrier NOx catalytic reduction catalyst is known (For example, see Patent Document 2).
[0009]
However, the storage reduction the NO x purification catalyst that carrying the alkali metal or alkaline earth metal with a carbonate or acetate salt, it is necessary to increase the NO x purification performance in the catalyst temperature above about 500 ° C.. Further, catalysts containing conventional perovskite-type composite oxide, for use in the purification of exhaust gas discharged from an internal combustion engine such as automobile engine, it is necessary to increase the NO x purification rate.
[0010]
Therefore, it is possible to exert the NO x purification performance excellent in catalyst temperature above about 500 ° C., improved exhaust gas purifying catalyst has been proposed. This catalyst is characterized in that at least one catalyst component of Pt, Pd, Rh, Au, Ag, and Ir is supported on a perovskite-type composite oxide containing at least two metal elements. , preferred perovskite-type composite oxide, La 1-x K x BO 3 (B is, Mn, Co, at least one of Fe, and Ni) structural formula or a 1-x of K x B 1-y Ti y K having the structural formula of O 3 (A is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, and Y, and B is at least one of Mn, Co, Fe, and Ni) A specific perovskite-type composite oxide is disclosed (for example, see Patent Document 3).
[0011]
[Patent Document 1]
JP-A-9-248458 [Patent Document 2]
JP-A-5-261289 [Patent Document 3]
JP 2001-269578 A
[Problems to be solved by the invention]
However, in the above perovskite-type composite oxide exhaust gas purifying catalyst obtained by loading a noble metal on the product, it was the improvement hot the NO x purification performance, it is impossible to sufficiently purify the NO x in a lean atmosphere at a low temperature. Further, an alkali metal storage reduction the NO x purification catalyst forms stable sulfate by sulfur contained in the fuel, performance by the so-called sulfur poisoning is also lowered.
[0013]
Accordingly, the present invention exhibits high the NO x purification performance even at a low temperature not high temperature only, and an object thereof to provide a highly storage-reduction type NOx purifying catalyst of the sulfur-poisoning resistance.
[0014]
[Means for Solving the Problems]
According to the present invention in order to achieve the above object, the following formula A 1-x Rb x M 1 -y-z Ti y R z O 3
(Where A represents one or more metals selected from the group consisting of La, Nd and Sm, M represents one or more metals selected from the group consisting of Mn, Fe, Co and Ni, and R represents Represents one or more metals selected from the group consisting of Pt, Pd and Rh, x represents a number satisfying 0.1 <x <1, y represents a number satisfying 0 <y <1, and z represents 0 Represents a number satisfying <z <1, where y> z and 0 <y + z <0.5)
An exhaust gas purifying catalyst comprising a perovskite-type composite metal oxide represented by the formula: This perovskite-type composite metal oxide may be supported on a carrier.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
A conventional exhaust gas purification catalyst containing a perovskite-type composite metal oxide is constituted by supporting a noble metal such as Pt on a perovskite-type composite metal oxide. On the other hand, the exhaust gas purifying catalyst of the present invention is characterized in that a part of the metal constituting the perovskite-type composite metal oxide is replaced with a noble metal, and the noble metal is arranged in the crystal lattice of the composite oxide. I do.
[0016]
That is, the exhaust gas purifying catalyst the formula A 1-x Rb of the present invention x M 1-y-z Ti y R z O 3
Of a perovskite-type composite metal oxide having the following structure: In the above formula, A represents one or more metals selected from the group consisting of La, Nd and Sm, and is preferably Nd, and M is one or more metals selected from the group consisting of Mn, Fe, Co and Ni. And preferably represents Mn, and R represents at least one metal selected from the group consisting of Pt, Pd and Rh, and is preferably Pt. In the formula, x represents a number satisfying 0.1 <x <1, and is preferably 0.3; y represents a number satisfying 0 <y <1, preferably 0.25; Represents a number satisfying 0 <z <1, and is preferably 0.05, provided that y> z, and 0 <y + z <0.5. A particularly preferred perovskite-type composite metal oxide is Nd 0.7 Rb 0.3 Nn 0.7 Ti 0.25 Pt 0.05 O 3 .
[0017]
Since the exhaust gas purification catalyst of the present invention has a noble metal in the crystal lattice of the perovskite-type composite metal oxide, the dispersion of the noble metal is smaller than in the case where the noble metal is supported on the perovskite-type composite metal oxide as in the related art. sex has been improved, as a result, the conventional catalyst and the NO x purification performance in a high temperature range which could not be sufficiently purified (500 ° C. or higher), the NO x purification at low temperature range (400 ° C. or less) Performance can be greatly improved. Furthermore, due to the high dispersibility of the noble metal, the contact between the alkali metal sulfate formed by sulfur poisoning and the noble metal is improved as compared with the conventional catalyst, and as a result, the decomposition of the sulfate is accelerated, after circulation also it can maintain the NO x purification performance is improved sulfur-poisoning resistance.
[0018]
This perovskite-type composite metal oxide having a noble metal has a metal compound selected from a metal nitrate, an acetate, and a chloride, and a metal oxide sol or the like so as to have a ratio of the metal constituting the metal oxide. After mixing, or after mixing and drying these metal compounds in an aqueous solution or suspension, they can be produced by heating to 400 to 1000 ° C. in air.
[0019]
In the present invention, the perovskite-type composite metal oxide may be supported on a carrier. As the carrier, a carrier that has been conventionally used as a carrier for an exhaust gas purifying catalyst can be used, and a porous monolith carrier having a honeycomb structure is preferable, and a cordierite honeycomb is particularly preferable.
[0020]
The loading of the metal oxide on the carrier can be performed by a known method, for example, a method of coating a slurry containing the metal oxide and the metal oxide sol on the carrier and firing the slurry. The amount of the metal oxide carried on the carrier can be arbitrarily determined, but it is preferable that alumina: perovskite-type composite metal oxide = 10: 1.
[0021]
The exhaust gas purifying catalyst of the present invention, by a known method such as placed in a suitable unit, disposed in an exhaust gas flow path to be discharged from the internal combustion engine such as an automobile engine, NO x, etc. in the exhaust gas Can be used as a catalyst for purifying the components.
[0022]
Hereinafter, the exhaust gas purifying catalyst of the present invention will be described more specifically based on examples, but the present invention is not limited thereto.
[0023]
【Example】
Example 1
52.28 g of neodymium nitrate, 7.54 g of rubidium nitrate, 34.23 g of manganese nitrate, 11.34 g of titania sol (STS-01 manufactured by Ishihara Sangyo,
[0024]
Comparative Example 1
53.97 g of neodymium nitrate, 7.78 g of rubidium nitrate, 35.34 g of manganese nitrate, 14.05 g of titania sol (STS-01 manufactured by Ishihara Sangyo,
[0025]
Comparative Example 2
25 g of alumina, 4.21 g of dinitrodiamine Pt nitric acid aqueous solution (8P manufactured by Cataler, Pt 4.4 wt%) were added to 200 mL of ion-exchanged water, and stirred at room temperature for 1 hour. Then, it was dehydrated at 120 ° C. for 2 hours and calcined at 500 ° C. for 2 hours. 25 g of the obtained powder and 4.78 g of rubidium nitrate were added to 200 mL of ion-exchanged water, stirred for 1 hour, dehydrated at 120 ° C. for 2 hours, calcined at 500 ° C. for 2 hours, and Rb = 0.35 mol / Pt = 11.58 g / Al 2 O 3 = 270 g of powder was obtained. The obtained powder was pelletized in the same manner as in Example 1.
[0026]
Evaluation of NO x purification performance 2 g of the above pellets were charged into a fixed bed flow type reactor (gas flow rate: 6.6 L / min), and a test was conducted under the following conditions.
Initial performance lean composition: NO = 500 ppm, C 3 H 6 = 667 ppm, CO = 0.1%, O 2 = 6.5%, CO 2 = 10%, H 2 O = 2%, N 2 = balance.
Rich composition: NO = 500 ppm, C 3 H 6 = 667 ppm, CO = 0.6%, O 2 = 0.4%, CO 2 = 10%, H 2 O = 2%, N 2 = balance.
After 10 minutes of the 600 ° C. rich treatment, lean / rich = 2/2 minutes was repeated at 600, 500, 400, 300, and 700 ° C. The output NO concentration (ppm) after 2 minutes of lean was measured and determined as the NO purification rate. NO purification rate (%) = (incoming NO concentration (500 ppm) −outgoing NO concentration (ppm)) × 100 / (incoming NO concentration (500 ppm)).
[0027]
Post-Durability Performance Samples after a 400 ° C. sulfur endurance test (lean and rich compositions with 100 ppm of SO 2 each mixed for 4/1 minutes and lasted for 4 hours) were evaluated in the same manner as initial performance.
[0028]
The above results are shown in FIGS. From these results, the exhaust gas purifying catalyst of the present invention has a significantly improved NOx purifying ability in a high temperature range of 600 ° C. or higher, and does not deteriorate even in a low temperature range (FIG. 1). Furthermore, sulfur poisoning degradation is also reduced (FIG. 2).
[0029]
【The invention's effect】
Exhaust gas purifying catalyst of the present invention show high the NO x purification performance even at a low temperature not high temperature only, and high sulfur-poisoning resistance, reducing the emissions in the exhaust gases emitted from an internal combustion engine of a motor vehicle engine can be, it is especially excellent in the ability to purify NO x.
[Brief description of the drawings]
FIG. 1 is a graph showing an initial NO x purification performance of a catalyst.
FIG. 2 is a graph showing the sulfur poisoning resistance of a catalyst.
Claims (2)
Ａ１−ｘＲｂｘＭ１−ｙ−ｚＴｉｙＲｚＯ３
（式中、ＡはＬａ、Ｎｄ及びＳｍからなる群より選ばれる１種以上の金属を表し、ＭはＭｎ、Ｆｅ、Ｃｏ及びＮｉからなる群から選ばれる１種以上の金属を表し、ＲはＰｔ、Ｐｄ及びＲｈからなる群から選ばれる１種以上の金属を表し、ｘは０．１＜ｘ＜１を満たす数字を表し、ｙは０＜ｙ＜１を満たす数字を表し、ｚは０＜ｚ＜１を満たす数字を表し、但しｙ＞ｚであり、０＜ｙ＋ｚ＜０．５である）
で表されるペロブスカイト型複合金属酸化物からなる排気ガス浄化触媒。The formula A 1-x Rb x M 1 -y-z Ti y R z O 3
(Where A represents one or more metals selected from the group consisting of La, Nd and Sm, M represents one or more metals selected from the group consisting of Mn, Fe, Co and Ni, and R represents Represents one or more metals selected from the group consisting of Pt, Pd and Rh, x represents a number satisfying 0.1 <x <1, y represents a number satisfying 0 <y <1, and z represents 0 Represents a number satisfying <z <1, where y> z and 0 <y + z <0.5)
An exhaust gas purification catalyst comprising a perovskite-type composite metal oxide represented by the formula:
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| WO2007115380A1 (en) * | 2006-04-12 | 2007-10-18 | Very Small Particle Company Pty Ltd | Sulfur resistant emissions catalyst |
| WO2007145216A1 (en) | 2006-06-13 | 2007-12-21 | Hitachi Maxell, Ltd. | Fine particle of perovskite oxide, particle having deposited perovskite oxide, catalyst material, catalyst material for oxygen reduction, catalyst material for fuel cell, and electrode for fuel cell |
-
2003
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| WO2007115380A1 (en) * | 2006-04-12 | 2007-10-18 | Very Small Particle Company Pty Ltd | Sulfur resistant emissions catalyst |
| EP2010317A1 (en) * | 2006-04-12 | 2009-01-07 | The Very Small Particle Company Pty Ltd | Sulfur resistant emissions catalyst |
| JP2009533206A (en) * | 2006-04-12 | 2009-09-17 | ベリー スモール パーティクル コンパニー リミテッド | Sulfur-resistant emission catalyst |
| AU2007236562B2 (en) * | 2006-04-12 | 2011-04-14 | Very Small Particle Company Pty Ltd | Sulfur resistant emissions catalyst |
| EP2010317A4 (en) * | 2006-04-12 | 2012-08-29 | Very Small Particle Company Ltd | Sulfur resistant emissions catalyst |
| CN101443119B (en) * | 2006-04-12 | 2013-03-13 | 微小分子股份有限公司 | Sulfur resistant emissions catalyst |
| US8609575B2 (en) | 2006-04-12 | 2013-12-17 | Very Small Particle Company Limited | Sulfur resistant emissions catalyst |
| WO2007145216A1 (en) | 2006-06-13 | 2007-12-21 | Hitachi Maxell, Ltd. | Fine particle of perovskite oxide, particle having deposited perovskite oxide, catalyst material, catalyst material for oxygen reduction, catalyst material for fuel cell, and electrode for fuel cell |
| US8007691B2 (en) | 2006-06-13 | 2011-08-30 | Hitachi Maxell Energy, Ltd. | Fine particle of perovskite oxide, particle having deposited perovskite oxide, catalyst material, catalyst material for oxygen reduction, catalyst material for fuel cell, and electrode for fuel cell |
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