JP4729681B2 - Method for producing perovskite complex oxide - Google Patents
Method for producing perovskite complex oxide Download PDFInfo
- Publication number
- JP4729681B2 JP4729681B2 JP2004061882A JP2004061882A JP4729681B2 JP 4729681 B2 JP4729681 B2 JP 4729681B2 JP 2004061882 A JP2004061882 A JP 2004061882A JP 2004061882 A JP2004061882 A JP 2004061882A JP 4729681 B2 JP4729681 B2 JP 4729681B2
- Authority
- JP
- Japan
- Prior art keywords
- complex oxide
- perovskite
- perovskite complex
- metal element
- nitrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000000463 material Substances 0.000 claims description 51
- 239000002243 precursor Substances 0.000 claims description 37
- 229910000510 noble metal Inorganic materials 0.000 claims description 34
- -1 ammonium ions Chemical class 0.000 claims description 22
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 18
- 229910052723 transition metal Inorganic materials 0.000 claims description 18
- 150000003839 salts Chemical class 0.000 claims description 15
- 229910002651 NO3 Inorganic materials 0.000 claims description 11
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 10
- 239000011707 mineral Substances 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000007864 aqueous solution Substances 0.000 claims description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 54
- 229910052751 metal Inorganic materials 0.000 description 29
- 239000002184 metal Substances 0.000 description 29
- 238000000034 method Methods 0.000 description 28
- 239000002244 precipitate Substances 0.000 description 25
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 23
- 239000006104 solid solution Substances 0.000 description 23
- 239000000243 solution Substances 0.000 description 21
- 229910052763 palladium Inorganic materials 0.000 description 20
- 239000002002 slurry Substances 0.000 description 20
- 239000000843 powder Substances 0.000 description 19
- 229910052746 lanthanum Inorganic materials 0.000 description 18
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 17
- 238000000634 powder X-ray diffraction Methods 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 16
- 238000010438 heat treatment Methods 0.000 description 16
- 239000007788 liquid Substances 0.000 description 16
- 239000012071 phase Substances 0.000 description 16
- 239000003054 catalyst Substances 0.000 description 13
- 150000002500 ions Chemical class 0.000 description 13
- 239000000047 product Substances 0.000 description 13
- 239000000126 substance Substances 0.000 description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 11
- 238000001035 drying Methods 0.000 description 10
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 9
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 9
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 235000010755 mineral Nutrition 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000012298 atmosphere Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 5
- 239000003513 alkali Substances 0.000 description 5
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 5
- 239000002131 composite material Substances 0.000 description 5
- 239000000543 intermediate Substances 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
- 239000010970 precious metal Substances 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 4
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 4
- 238000004438 BET method Methods 0.000 description 4
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- 150000004703 alkoxides Chemical class 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 239000001099 ammonium carbonate Substances 0.000 description 4
- 235000011114 ammonium hydroxide Nutrition 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000010948 rhodium Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 150000001342 alkaline earth metals Chemical class 0.000 description 3
- 235000012501 ammonium carbonate Nutrition 0.000 description 3
- 238000007664 blowing Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 3
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 150000002823 nitrates Chemical class 0.000 description 3
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 3
- 230000001376 precipitating effect Effects 0.000 description 3
- 229910052703 rhodium Inorganic materials 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000012876 carrier material Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 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
- 239000000203 mixture Substances 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 229910052712 strontium Inorganic materials 0.000 description 2
- DHEQXMRUPNDRPG-UHFFFAOYSA-N strontium nitrate Chemical compound [Sr+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O DHEQXMRUPNDRPG-UHFFFAOYSA-N 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229910000013 Ammonium bicarbonate Inorganic materials 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
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- FCUFAHVIZMPWGD-UHFFFAOYSA-N [O-][N+](=O)[Pt](N)(N)[N+]([O-])=O Chemical compound [O-][N+](=O)[Pt](N)(N)[N+]([O-])=O FCUFAHVIZMPWGD-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910001420 alkaline earth metal ion Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910003445 palladium oxide Inorganic materials 0.000 description 1
- JQPTYAILLJKUCY-UHFFFAOYSA-N palladium(ii) oxide Chemical compound [O-2].[Pd+2] JQPTYAILLJKUCY-UHFFFAOYSA-N 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 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
- 239000012266 salt solution Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 229910001948 sodium oxide Inorganic materials 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000013076 target substance Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Description
本発明は，ペロブスカイト型複合酸化物およびその製造方法に係り，とくに化学合成および排ガス浄化などに適用可能な比較的比表面積が大きくて高活性なペロブスカイト型複合酸化物系触媒を低コストで工業生産する技術に関する。 The present invention relates to a perovskite complex oxide and a method for producing the same, and in particular, industrial production of a highly active perovskite complex oxide catalyst having a relatively large specific surface area applicable to chemical synthesis and exhaust gas purification at low cost. Related to technology.
一般に，触媒材料に用いられる活性金属種は，その表面積の大小が触媒活性に大きく影響する。従って，活性金属種が担体上に微細且つ高分散に担持されている程，活性金属種の表面積が大きくなり，触媒活性は向上する。 In general, the active metal species used in the catalyst material has a large influence on the catalytic activity because of the surface area. Therefore, the more the active metal species are supported on the carrier in a finer and higher dispersion, the larger the surface area of the active metal species and the higher the catalytic activity.
従来の代表的な活性金属種の高分散な担持方法は，高表面積な担体に活性金属種化合物塩溶液を含浸して乾固・焼成する方法であった。この様にして担持された微細な活性金属種粒子は，それ自身が持つ大きな表面エネルギーのため，長期間の加熱により相互に凝集してシンタリングを起こし，失活する問題があった。 Conventionally, a highly dispersed supporting method of a typical active metal species is a method of impregnating an active metal species compound salt solution into a high surface area support and drying and baking. The fine active metal seed particles supported in this way have a problem of being deactivated due to their large surface energy, causing aggregation due to long-term heating and sintering.
近年，新たな担持方法も試みられている。竹平は非特許文献１に報告しているように，活性金属種を構造中に均質に固溶させたペロブスカイト型酸化物前駆体を調整し，これを加熱・還元して構造中の活性金属種を表面に担持している。構造中にイオンとして存在する金属が還元されるときには高分散な超微粒子を生成し，また，この様にして生成した超微粒子金属種は母体との親和性が強く，安定でシンタリングを起こし難いという。 In recent years, new loading methods have been tried. As reported in Non-Patent Document 1, Takehira prepared a perovskite-type oxide precursor in which an active metal species was homogeneously dissolved in the structure, and heated and reduced it to reduce the active metal species in the structure. Is supported on the surface. When metals present as ions in the structure are reduced, highly dispersed ultrafine particles are produced. The ultrafine metal species produced in this way have a strong affinity with the matrix and are stable and difficult to sinter. That's it.
この方法を更に発展させて実用化に至った例も存在する。田中らは非特許文献２に報告しているように，希土類−遷移元素系ペロブスカイト化合物の構造中に活性金属種である貴金属元素を固溶させたペロブスカイト触媒において，自動車排ガス中の還元と酸化雰囲気変動を利用して活性金属種を『微細かつ高分散に析出』と『ペロブスカイト格子中に固溶』を繰り返させることにより，高温に晒されてもシンタリングやそれに伴う失活を生じない触媒を開発している。このように活性金属種を構造中に固溶させたペロブスカイト型複合酸化物は，活性および耐久性に優れた触媒材料となり得る。また，その貴金属元素の固溶率が高ければ高いほど，貴金属が活性金属種として機能する。 There are also examples in which this method has been further developed and put to practical use. As reported in Non-Patent Document 2, Tanaka et al. In a perovskite catalyst in which a noble metal element, which is an active metal species, is dissolved in the structure of a rare earth-transition element-based perovskite compound. By making use of fluctuations, the active metal species can be repeatedly “precipitated finely and highly dispersed” and “solid solution in the perovskite lattice” to create a catalyst that does not cause sintering or deactivation associated with exposure to high temperatures. We are developing. Thus, the perovskite type complex oxide in which the active metal species is dissolved in the structure can be a catalyst material excellent in activity and durability. In addition, the higher the solid solution ratio of the noble metal element, the more the noble metal functions as an active metal species.
活性金属種を構造中に固溶させたペロブスカイト型複合酸化物の製造方法に関しては，いくつかの方法が知られている。通常の触媒作製で行われる含浸・蒸発乾固・焼成のプロセスやクエン酸錯体法，シアン塩分解法，フリーズドライ法などである。特許文献１ではアルコキシド原料を貴金属塩化合物溶液で加水分解することにより構造中に貴金属を固溶させたペロブスカイト型複合酸化物が報告されている。
前記の従来技術において，次のような問題がある。活性種に用いられるＰｄに代表される貴金属元素は，極めて沈殿し難い安定な錯体を生成するため，共沈法などの安価な製法である湿式反応によってペロブスカイト複合酸化物構造中に固溶させることは非常に困難である。活性金属種をペロブスカイト複合酸化物構造中に固溶させる処法として，従来から行われている含浸・蒸発乾固・焼成の一連の操作によって行う場合には，１０００℃近い高温での焼成・結晶化を必要とする（例えば特開昭50-83295号公報や特開昭50-78567号公報参照）ために，担体となるペロブスカイト複合酸化物の比表面積が低下し，触媒として使用された際に期待される高い活性が得られない。 The above prior art has the following problems. The noble metal elements represented by Pd used for the active species form a stable complex that is extremely difficult to precipitate. Therefore, the precious metal element is dissolved in the perovskite complex oxide structure by a wet reaction, which is an inexpensive method such as coprecipitation. Is very difficult. When the active metal species is dissolved in the perovskite complex oxide structure by a series of conventional impregnation, evaporation, drying, and firing operations, firing and crystallization at a high temperature close to 1000 ° C. When the catalyst is used as a catalyst, the specific surface area of the perovskite composite oxide used as a carrier is reduced because of the necessity of crystallization (see, for example, JP-A-50-83295 and JP-A-50-78567). The expected high activity cannot be obtained.
この点を改善するために，クエン酸分解法，シアン塩分解法, フリーズドライ法, アルコキシド法などが提案されている。これらの方法では５００〜７００℃の温度範囲からペロブスカイト型複合酸化物を得ることができるので，比表面積の高いペロブスカイト複合酸化物を得られる。しかし，クエン酸錯体法では，乾燥，焼成時に生成物が異常な体膨張をするために工業的に量産が困難であること，シアン塩分解法では，原料として有毒なシアン塩を用いなければならないこと，フリーズドライ法では低温減圧が必要であるため複雑な装置が必要となること，アルコキシド法は原料となる金属アルコキシドが非常に高価である。従って，いずれの製法にも環境対策及び製造コストの点で工業的な製造法としては問題がある。 In order to improve this point, citric acid decomposition method, cyanide decomposition method, freeze-dry method, alkoxide method, etc. have been proposed. In these methods, a perovskite complex oxide can be obtained from a temperature range of 500 to 700 ° C., so that a perovskite complex oxide having a high specific surface area can be obtained. However, the citric acid complex method is difficult to industrially mass-produce because the product undergoes abnormal body expansion during drying and firing, and the cyanide salt decomposition method requires the use of toxic cyanide salts as raw materials. The freeze-drying method requires a low-temperature pressure reduction and requires a complicated apparatus, and the alkoxide method requires a very expensive metal alkoxide as a raw material. Therefore, both production methods have problems as industrial production methods in terms of environmental measures and production costs.
したがって本発明は，低コストでかつ有害原料の使用や有害物質の発生を伴わない安全な製造方法により，ペロブスカイト型複合酸化物の高比表面積化と，活性金属種の構造中への固溶化を両立させることを課題としたものである。すなわち，活性金属種を構造中に固溶し且つ高比表面積を有したペロブスカイト型複合酸化物材料を得ること，並びにかかる材料を工業的規模で再現性良く製造できる方法を提供することを目的とする。 Therefore, the present invention achieves a high specific surface area of the perovskite-type composite oxide and solid solution of the active metal species in the structure by a low-cost and safe manufacturing method that does not involve the use of harmful raw materials or generation of harmful substances. The challenge is to achieve both. That is, an object of the present invention is to obtain a perovskite type complex oxide material in which active metal species are dissolved in the structure and have a high specific surface area, and to provide a method capable of producing such a material on an industrial scale with good reproducibility. To do.
本発明によれば，希土類元素の少なくとも１種と遷移金属元素の少なくとも１種を含有する前駆体物質を熱処理してペロブスカイト型複合酸化物相を生成させるさいに，該前駆体物質として非晶質の物質を使用し，この非晶質物質に貴金属元素を含有させ，より具体的には，この粉状の非晶質物質を，貴金属元素イオンを含む溶液でスラリー化し，このスラリーを乾燥させることによって該非晶質物質に貴金属元素を含有させ，この乾燥後の固形物を前記の熱処理に供すること，を特徴とする貴金属元素含有のペロブスカイト型複合酸化物の製造法を提供する。 According to the present invention, when a precursor material containing at least one rare earth element and at least one transition metal element is heat-treated to form a perovskite complex oxide phase, the precursor material is amorphous. This amorphous material is used to contain a noble metal element. More specifically, this powdery amorphous material is slurried with a solution containing noble metal element ions, and the slurry is dried. Thus, a method for producing a noble metal element-containing perovskite complex oxide is provided, wherein the amorphous substance is made to contain a noble metal element and the dried solid is subjected to the heat treatment.
ここで，非晶質物質を貴金属元素イオンを含む溶液でスラリー化するさいに，硝酸イオンとアンモニウムイオンを液中に共存させ，液のｐＨを６以上に調整することが好ましく，硝酸イオンとアンモニウムイオンの合計量が，非晶質物質中の希土類元素と遷移金属元素の合計量に対して，モル比で０.６倍より大きくするのが好ましい。ペロブスカイト型複合酸化物相を得るための熱処理温度は４００〜７００℃の範囲でよく，このために比表面積の大きなペロブスカイト型複合酸化物を得ることができる。 Here, when slurrying an amorphous substance with a solution containing precious metal element ions, nitrate ions and ammonium ions are preferably allowed to coexist in the liquid, and the pH of the liquid is preferably adjusted to 6 or more. The total amount of ions is preferably greater than 0.6 times in molar ratio with respect to the total amount of rare earth elements and transition metal elements in the amorphous material. The heat treatment temperature for obtaining the perovskite complex oxide phase may be in the range of 400 to 700 ° C. Therefore, a perovskite complex oxide having a large specific surface area can be obtained.
なお，粉状の非晶質物質を製造するには，希土類元素の鉱酸塩と遷移金属元素の鉱酸塩を溶解した水溶液と沈殿剤を反応温度６０℃以下で且つｐＨ６以上で反応させて沈殿を生成させ，この沈殿を採取すればよい。場合によっては，希土類元素の鉱酸塩と遷移金属元素の鉱酸塩を溶解した水溶液をアンモニアで中和処理した後に炭酸ガスを吹き込むことによって沈殿を生成させ，この沈殿を採取すればよい。 In order to produce a powdery amorphous substance, an aqueous solution in which a rare earth element mineral salt and a transition metal element mineral salt are dissolved and a precipitant are reacted at a reaction temperature of 60 ° C. or lower and a pH of 6 or higher. A precipitate is generated and collected. In some cases, an aqueous solution in which a rare earth element mineral salt and a transition metal element mineral salt are dissolved is neutralized with ammonia, and then a precipitate is generated by blowing carbon dioxide, and this precipitate may be collected.
このような製造法により，本発明によれば，希土類元素の少なくとも１種と遷移金属元素の少なくとも１種を含有するペロブスカイト型複合酸化物において，その結晶中に貴金属元素を含有し且つＢＥＴ法による比表面積が１０ｍ2/ｇを超える値を有する貴金属元素含有のペロブスカイト型複合酸化物が得られる。そのさい，含有する貴金属元素のうち８０％以上が結晶格子中に固溶しているものが得られる。 According to the present invention, according to the present invention, in the perovskite type complex oxide containing at least one rare earth element and at least one transition metal element, the crystal contains the noble metal element and the BET method. A perovskite complex oxide containing a noble metal element having a specific surface area exceeding 10 m 2 / g is obtained. At that time, 80% or more of the precious metal element contained is obtained as a solid solution in the crystal lattice.
本発明によるペロブスカイト型複合酸化物は，活性金属種を構造中に固溶し，また比表面積も大きいため，還元雰囲気下で活性金属種を表面に析出させた場合に，活性金属種が微細かつ高分散に析出する。このため，これまでのものに無い高活性で高耐熱な触媒材料となり得る。 The perovskite complex oxide according to the present invention has active metal species dissolved in the structure and has a large specific surface area. Therefore, when the active metal species is deposited on the surface in a reducing atmosphere, the active metal species is fine and Precipitates with high dispersion. For this reason, it can be a highly active and highly heat-resistant catalyst material that has never existed before.
本発明に従うペロブスカイト型複合酸化物は，一般式ＲＴＯ3（Ｒ：希土類元素の少なくとも１種，Ｔ：遷移金属元素の少なくとも１種）で表すことができ，これに貴金属元素Ｐを含有させたものである。希土類元素Ｒも広義には遷移金属と言えないことはないけれど，本発明でいう遷移金属元素Ｔは，その金属または金属イオンの３ｄの電子軌道に電子が埋められておらず４ｓとの間で電子が遷移する金属例えばＮｉ，Ｃｏ，Ｆｅ，Ｍｎ，Ｃｒ，Ｖ，Ｔｉ，Ｃｕ等が挙げられ，同様に４ｆ電子軌道に電子が埋められていない金属例えばＺｒやＮｂ等も含むことができる。貴金属元素Ｒとしては特に限定されないが，Ｙ，Ｌａ，Ｃｅ，Ｎｄ，Ｓｍ，Ｐｒ等であることができる。また本発明において含有させる貴金属元素ＰとしてはＰｔ，Ｐｄ，Ｒｕ，Ｒｈ等が挙げられる。 The perovskite type complex oxide according to the present invention can be represented by the general formula RTO 3 (R: at least one rare earth element, T: at least one transition metal element), and a noble metal element P contained therein. It is. Although the rare earth element R cannot be said to be a transition metal in a broad sense, the transition metal element T in the present invention is not filled with electrons in the 3d electron orbit of the metal or metal ion between 4 s. Examples include metals in which electrons transition, such as Ni, Co, Fe, Mn, Cr, V, Ti, and Cu. Similarly, metals in which electrons are not buried in 4f electron orbits such as Zr and Nb can also be included. The noble metal element R is not particularly limited, but may be Y, La, Ce, Nd, Sm, Pr or the like. Examples of the noble metal element P to be contained in the present invention include Pt, Pd, Ru, Rh and the like.
ＲとＴおよびＰを主要構成成分としたうえ，これらＲまたはＴの一部をアルカリ金属またはアルカリ土類金属と置換することもできる。このようなアルカリまたはアルカリ土類金属でＲまたはＴの一部を置換したペロブスカイト型複合酸化物を製造する場合にも，アルカリまたはアルカリ土類金属のイオンを沈殿生成のための液に含有させればよく，これによって，前記同様に，非晶質の前駆体物質を得ることができる。アルカリまたはアルカリ土類金属としては，Ｌｉ，Ｋ．Ｎａ，Ｍｇ，Ｓｒ，Ｃａ，Ｂａ等を挙げることができる。また，本発明の効果を妨げない範囲内であれば，アルミナ，シリカ，チタニア，ジルコニアなどの担体材料やこれらの複合酸化物といった耐熱性担体材料を前駆体物質に添加することも可能である。この場合には，このような担持物質とともに前駆体物質を熱処理することによって，これらの担体材料にペロブスカイト型複合酸化物が担持された状態のものが得られる。 R, T, and P can be used as main components, and a part of R or T can be replaced with an alkali metal or an alkaline earth metal. In the case of producing a perovskite type composite oxide in which a part of R or T is substituted with such an alkali or alkaline earth metal, alkali or alkaline earth metal ions can be contained in the solution for precipitation. As a result, an amorphous precursor material can be obtained as described above. Examples of alkali or alkaline earth metals include Li, K.I. Na, Mg, Sr, Ca, Ba, etc. can be mentioned. In addition, a carrier material such as alumina, silica, titania, zirconia or a heat resistant carrier material such as a composite oxide thereof can be added to the precursor material as long as the effect of the present invention is not hindered. In this case, the precursor material is heat-treated together with such a support material to obtain a state in which the perovskite complex oxide is supported on these support materials.
本発明では，このようなＲＴＯ3型のペロブスカイト複合酸化物の構造中に（Ｔサイトに）効率よく貴金属元素を固溶（置換）させることと，比表面積の大きな形態でこの複合酸化物を得ることを目的としたものであるが，後者の高比表面積化を図るには，ペロブスカイト型複合酸化物相を低温で晶出させることが必要である。この点については，同一出願人に係る特願２００３−０９００８０号に記載したように非晶質の前駆体物質を用いて熱処理することによって達成できる。そして，この非晶質物質に貴金属元素を適正に含有させたうえで，熱処理すると構造中に高い比率で貴金属元素を固溶させることができることがわかった。 In the present invention, a noble metal element is efficiently dissolved (substituted) in the structure of such an RTO 3 type perovskite complex oxide (at the T site), and this complex oxide is obtained in a form having a large specific surface area. In order to increase the specific surface area of the latter, it is necessary to crystallize the perovskite complex oxide phase at a low temperature. This can be achieved by performing a heat treatment using an amorphous precursor material as described in Japanese Patent Application No. 2003-090080 of the same applicant. Then, it was found that the noble metal element can be dissolved in a high ratio in the structure when the amorphous material is appropriately mixed with the noble metal element and then heat-treated.
まず粉状の「非晶質の前駆体物質」について説明する。従来から報告されているペロブスカイト型複合酸化物の反応では，水酸化物，炭酸塩，蓚酸塩，酢酸塩，シアン塩，酸化物などの結晶性中間物質を経由していると言えるが，結晶性の中間物質を経由して目的物質であるペロブスカイト型複合酸化物を得ようとした場合には，必然的に高温で長時間の熱処理を必要となることになる。結晶性中間物質を経ないならば，低温での熱処理でペロブスカイト型複合酸化物が得られる可能性がある。本発明では，この点に着目し，希土類元素Ｒの少なくとも１種と遷移金属元素Ｔの少なくとも１種を含有する前駆体物質を熱処理してペロブスカイト（ＲＴＯ3）型の複合酸化物相を生成させるさいに，その前駆体物質として該複合酸化物を生成するに必要な量比のＲおよびＴ成分を含有する非晶質物質，すなわちＸ線回折像はブロードな状態のままで，明確なピークは存在しない非晶質物質を使用する。この物質はペロブスカイト型複合酸化物を得るための熱処理温度に至るまでその非晶質状態を維持していることが望ましい。 First, the powdery “amorphous precursor material” will be described. In the reaction of perovskite type complex oxides reported so far, it can be said that it passes through crystalline intermediates such as hydroxide, carbonate, oxalate, acetate, cyanate and oxide. When an attempt is made to obtain a perovskite type complex oxide, which is the target substance, via an intermediate material, it will inevitably require heat treatment at a high temperature for a long time. If it does not go through a crystalline intermediate substance, a perovskite complex oxide may be obtained by heat treatment at low temperature. In the present invention, focusing on this point, a precursor material containing at least one rare earth element R and at least one transition metal element T is heat-treated to produce a perovskite (RTO 3 ) type complex oxide phase. At the same time, the amorphous material containing the R and T components in the quantitative ratio necessary to produce the composite oxide as the precursor material, that is, the X-ray diffraction image remains in a broad state, and a clear peak is obtained. Use non-existing amorphous material. It is desirable that this substance maintain its amorphous state until reaching the heat treatment temperature for obtaining the perovskite complex oxide.
この非晶質物質を熱処理すると前記のような結晶性中間物質を経ずに直接ペロブスカイト型複合酸化物を得ることができる。その熱処理温度も４００℃程度の低温からペロブスカイト型複合酸化物相を生成させることが可能であり，実際には４００℃〜７００℃の熱処理温度において，結晶性中間物質を経ずにペロブスカイト型複合酸化物相を生成させることができる。 When this amorphous material is heat-treated, a perovskite complex oxide can be obtained directly without passing through the crystalline intermediate material as described above. It is possible to generate a perovskite type complex oxide phase from a low temperature of about 400 ° C., and in fact, at a heat treatment temperature of 400 ° C. to 700 ° C., a perovskite type complex oxidation without passing through a crystalline intermediate substance. A physical phase can be generated.
かような前駆体物質としての非晶質物質は，ＲイオンとＴイオンを含有する水溶液から沈殿剤を用いて沈殿させるという湿式法で得ることができる。具体的には，Ｒの鉱酸塩とＴの鉱酸塩を溶解した水溶液と炭酸アルカリを反応温度６０℃以下で且つｐＨ６〜１０の範囲で反応させて得た沈殿生成物を液から分離し，洗浄・乾燥することによって得ることができる。より具体的には，Ｒの硝酸塩，硫酸塩，塩化物等の水溶性鉱酸塩と，Ｔの硝酸塩，硫酸塩，塩化物等の水溶性鉱酸塩を，Ｒ元素とＴ元素のモル比がほぼ１：１となるように溶解した水溶液を準備し（Ｒ元素は２成分以上であってもよく，Ｔ元素も２成分以上であってもよい。その場合にも両者の全体としてモル比がほぼ１：１となるように各成分を溶解するのがよい），沈殿剤を使用して沈殿させる。ただし，Ｒ元素とＴ元素のモル比は，理想的にはほぼ１：１とするのがよいが，必ずしも１：１ではなくても，ペロブスカイト型複合酸化物を形成できることもある。したがって，Ｒ元素とＴ元素のモル比は１：１から多少ずれても，ペロブスカイト型複合酸化物が形成できるような値であればよい。 Such an amorphous material as a precursor material can be obtained by a wet method in which precipitation is performed from an aqueous solution containing R ions and T ions using a precipitant. Specifically, the precipitation product obtained by reacting an aqueous solution in which R mineral salt and T mineral salt are dissolved with alkali carbonate at a reaction temperature of 60 ° C. or lower and in the range of pH 6 to 10 is separated from the liquid. , Can be obtained by washing and drying. More specifically, water-soluble mineral salts such as nitrates, sulfates, and chlorides of R and water-soluble mineral salts such as nitrates, sulfates, and chlorides of T, the molar ratio of R element to T element Is prepared so as to be approximately 1: 1 (the R element may be two or more components, and the T element may be two or more components. Each component should be dissolved so that is approximately 1: 1) and precipitated using a precipitating agent. However, the molar ratio of R element to T element is ideally about 1: 1, but a perovskite type complex oxide may be formed even if it is not necessarily 1: 1. Therefore, even if the molar ratio of the R element and the T element is slightly deviated from 1: 1, it may be a value that can form a perovskite complex oxide.
沈殿を生成させる液中のＲおよびＴのイオン濃度は，用いる塩類の溶解度によって上限が決まるが，Ｒおよび／またはＴの結晶性化合物が析出しない状態が望ましく，通常は，ＲとＴの合計イオン濃度が０.０１〜０.６０ mol/L程度の範囲であるのが望ましい。 The upper limit of the ion concentration of R and T in the solution that generates the precipitate is determined by the solubility of the salt used, but it is desirable that the crystalline compound of R and / or T is not precipitated. The concentration is desirably in the range of about 0.01 to 0.60 mol / L.
この液から非晶質の沈殿を得るには沈殿剤を用いるが，沈殿剤としては，炭酸ナトリウム，炭酸水素ナトリウム，炭酸アンモニウム，炭酸水素アンモニウム等を使用することができ，必要に応じて，水酸化ナトリウム，アンモニア等の塩基を加えることも可能である。また，水酸化ナトリウム，アンモニア等のアルカリを用いて沈殿を形成した後，炭酸ガスを吹き込むことによっても高比表面積ペロブスカイト型複合酸化物の前駆体である非晶質材料を得ることも可能である。より具体的には，アンモニア水を添加しながらｐＨを６以上，好ましくは８以上に調整した後，炭酸ガスを吹き込むことによって良好な非晶質材料を得ることができる。 In order to obtain an amorphous precipitate from this solution, a precipitant is used. As the precipitant, sodium carbonate, sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, etc. can be used. It is also possible to add a base such as sodium oxide or ammonia. It is also possible to obtain an amorphous material that is a precursor of a high specific surface area perovskite complex oxide by blowing a carbon dioxide gas after forming a precipitate using an alkali such as sodium hydroxide or ammonia. . More specifically, a good amorphous material can be obtained by blowing carbon dioxide gas after adjusting the pH to 6 or more, preferably 8 or more while adding ammonia water.
非晶質の沈殿を得るには液のｐＨを６以上，好ましくは６〜１１の範囲に制御するのがよい。ｐＨが６未満の領域では，希土類元素Ｒが沈殿を形成しない場合があるので不適切である。他方，ｐＨが１１を超える領域では，生成する沈殿の非晶質化が十分に進行せずに，水酸化物などの結晶性の沈殿を形成する場合があるため不適切である。また，非晶質の沈殿を得るには，反応温度を６０℃以下にするのがよい。６０℃を超える温度領域で反応を開始した場合，希土類金属元素Ｒまたは遷移金属Ｔの結晶性の化合物粒子が生成する場合があり，前駆体物質の非晶質化を妨げるので好ましくない。 In order to obtain an amorphous precipitate, the pH of the solution should be controlled to 6 or more, preferably in the range of 6 to 11. In the region where the pH is less than 6, the rare earth element R may not form a precipitate, which is inappropriate. On the other hand, in the region where the pH exceeds 11, the resulting precipitate is not sufficiently amorphized and may form a crystalline precipitate such as a hydroxide, which is inappropriate. In order to obtain an amorphous precipitate, the reaction temperature is preferably 60 ° C. or lower. When the reaction is started in a temperature range exceeding 60 ° C., crystalline compound particles of rare earth metal element R or transition metal T may be generated, which is not preferable because it prevents the precursor material from becoming amorphous.
図１は後記参考例１の沈殿物の乾燥品を温度を変えて熱処理した場合の各熱処理品のＸ線回折パターンを対比したものであるが，熱処理する前の乾燥品はブロードなパターンをもつ非晶質物質であり，これを４００℃で熱処理しても非晶質状態を維持していること，そして，５００℃という比較的低い温度領域からＬａＣｏＯ3のペロブスカイト酸化物相が生成することがわかる。 FIG. 1 compares the X-ray diffraction pattern of each heat-treated product when the dried product of the precipitate of Reference Example 1 described below is heat-treated at different temperatures, but the dried product before the heat-treatment has a broad pattern. It is an amorphous substance that remains amorphous even when heat-treated at 400 ° C. and that a LaCoO 3 perovskite oxide phase is generated from a relatively low temperature range of 500 ° C. Recognize.
このようにして粉状で非晶質の前駆体物質を得ることができるが，この非晶質物質に貴金属元素を適切に含有させて，４００〜７００℃で熱処理すると，本発明で目的とする高い比表面積を有し且つ構造中に貴金属元素を含有したペロブスカイト型複合酸化物を得ることができる。以下に，この貴金属元素を非晶質物質に含有させる方法を説明する。ここで，貴金属元素としては，Ｐｔ，Ｐｄ，Ｒｕ，Ｒｈ等が挙げられる。貴金属元素を含有させる量は，ペロブスカイト相の生成を妨げない量であれば，とくに制限はない。 In this way, a powdery and amorphous precursor material can be obtained, but when the amorphous material is appropriately added with a noble metal element and heat-treated at 400 to 700 ° C., the object of the present invention is obtained. A perovskite complex oxide having a high specific surface area and containing a noble metal element in the structure can be obtained. Hereinafter, a method for incorporating this noble metal element into an amorphous material will be described. Here, examples of the noble metal element include Pt, Pd, Ru, Rh and the like. The amount of noble metal element is not particularly limited as long as it does not prevent the formation of the perovskite phase.
本発明によれば，貴金属元素を前記の非晶質物質に含有させる方法として，この粉状の非晶質物質を，貴金属元素イオンを含む溶液でスラリー化し，このスラリーを乾燥させるという方法を採用する。そのさい，硝酸イオンとアンモニウムイオンをスラリー液中に共存させ，液のｐＨを６以上に調整するのがよい。また，スラリー中の硝酸イオンとアンモニウムイオンの合計量が，非晶質物質中の希土類元素と遷移金属元素の合計量に対して，モル比で０.６倍以上とするのがよい。以下にその好ましい態様を説明する。 According to the present invention, as a method of incorporating the noble metal element into the amorphous material, a method is adopted in which the powdery amorphous material is slurried with a solution containing noble metal element ions and the slurry is dried. To do. At that time, nitrate ions and ammonium ions are preferably allowed to coexist in the slurry liquid and the pH of the liquid is adjusted to 6 or more. The total amount of nitrate ions and ammonium ions in the slurry is preferably 0.6 times or more in molar ratio with respect to the total amount of rare earth elements and transition metal elements in the amorphous material. The preferable aspect is demonstrated below.
粉状の非晶質物質を，貴金属元素イオンを含む溶液でスラリー化するとは，粉状の非晶質物質と貴金属の可溶性塩を水に添加すること同義であり，実際には後者の操作を行えばよい。そのさい，硝酸イオンとアンモニウムイオンも液中に共存させるのがよい。貴金属元素の可溶性塩としては，硝酸塩，塩化物などの水溶性塩を用いることができるが，貴金属元素のイオンを供給することが出来れば特にこれらに限定されない。硝酸イオン, アンモニウムイオンについても同様である。 Slurry of a powdery amorphous substance with a solution containing precious metal element ions is synonymous with adding a powdery amorphous substance and a soluble salt of a precious metal to water. Just do it. At that time, nitrate and ammonium ions should coexist in the liquid. As a soluble salt of a noble metal element, a water-soluble salt such as nitrate or chloride can be used, but it is not particularly limited as long as ions of the noble metal element can be supplied. The same applies to nitrate ions and ammonium ions.
このスラリーは，固形分としては前述の非晶質物質，液中に溶けている成分としては貴金属元素のイオン，硝酸イオンおよびアンモニウムイオンを含んでいるのが好ましく，固形分としての非晶質物質は，前述したように一たん沈殿物として液から分離した粉体（沈殿物を液から固液分離し，洗浄，乾燥したもの）を使用するのが好ましいが，必ずしも，それに限られない。非晶質の前駆体物質を製造するさいに，希土類元素および遷移金属元素の原料として硝酸塩を用いるか若しくは硝酸を添加し，沈殿剤にアンモニア若しくはアンモニウムイオンを含む化合物を用いた場合には，生成した沈殿の固液分離を行わず，この沈殿を含むスラリーに，貴金属の可溶性塩の化合物を添加することによって，同様に目的とするスラリー，すなわち固形分としては前述の非晶質物質（該沈殿），液中に溶けている成分としては貴金属元素のイオン，硝酸イオンおよびアンモニウムイオンを含むスラリーを得ることもできる。 The slurry preferably contains the above-mentioned amorphous substance as a solid content, and contains noble metal element ions, nitrate ions, and ammonium ions as components dissolved in the liquid. As described above, it is preferable to use the powder separated from the liquid as a precipitate as described above (the precipitate is solid-liquid separated from the liquid, washed and dried), but is not necessarily limited thereto. When amorphous precursor materials are produced, nitrates are used as raw materials for rare earth elements and transition metal elements, or when nitric acid is added and a compound containing ammonia or ammonium ions is used as a precipitating agent. By adding a compound of a noble metal soluble salt to the slurry containing this precipitate without solid-liquid separation of the precipitate, the target slurry, ie, the above-mentioned amorphous substance (the precipitate ), Slurry containing noble metal element ions, nitrate ions and ammonium ions can be obtained as components dissolved in the liquid.
ここで，非晶質の前駆体物質を分散させたスラリー中の硝酸イオンおよびアンモニウムイオンの量は，該前駆体物質を構成する遷移金属元素と希土類元素の合計モル数に対して，０.６倍より大きくすることが望ましい。０.６倍以下では，後記の比較例４や５にも示したが，後の熱処理の段階で，ペロブスカイト型複合酸化物相以外の不純物相が生成しやすくなる。また，この分散スラリーのｐＨは，前述の通り非晶質物質をスラリー中に安定して存在させるためにｐＨ≧６に制御するのが望ましい。 Here, the amount of nitrate ion and ammonium ion in the slurry in which the amorphous precursor material is dispersed is 0.6 relative to the total number of moles of transition metal element and rare earth element constituting the precursor material. It is desirable to make it larger than twice. When the ratio is 0.6 times or less, as shown in Comparative Examples 4 and 5 described later, an impurity phase other than the perovskite complex oxide phase is likely to be generated in the later heat treatment stage. Further, it is desirable to control the pH of the dispersion slurry to be pH ≧ 6 so that the amorphous substance is stably present in the slurry as described above.
このスラリーは，次いで乾燥処理を行う。乾燥処理は，スラリーから水を蒸発させること（蒸発乾固）を原則とするものである。濾過等の固液分離方法で液相と固相を分離する方法は好ましくない。乾燥処理の手段としては，自然乾燥，加熱乾燥，真空乾燥，スプレードライ等が採用できる。また，必要があれば，乾燥処理後に粉砕処理や分級処理を実施しても良い。 This slurry is then dried. In principle, the drying process is to evaporate water from the slurry (evaporation to dryness). A method of separating the liquid phase and the solid phase by a solid-liquid separation method such as filtration is not preferable. Natural drying, heat drying, vacuum drying, spray drying, or the like can be employed as a drying process. If necessary, pulverization or classification may be performed after the drying process.
乾燥処理によって得た固形物は，次いでペロブスカイト型複合酸化物とするための熱処理に供する。熱処理温度は，ペロブスカイト型複合酸化物を得られる限りでは特に限定されず，通常は，４００〜１０００℃程度でペロブスカイト型複合酸化物となるが，比表面積を高い状態に維持するには，この温度範囲内でできるだけ低くするのがよく，このために４００〜７００℃の範囲が好ましい。熱処理雰囲気は，大気又は酸化性雰囲気であれば良く，ペロブスカイト型複合酸化物が得られる酸素濃度，温度範囲ならば窒素雰囲気中等でもよい。 The solid obtained by the drying treatment is then subjected to a heat treatment for obtaining a perovskite complex oxide. The heat treatment temperature is not particularly limited as long as a perovskite type complex oxide can be obtained. Usually, the perovskite type complex oxide is formed at about 400 to 1000 ° C. However, this temperature is required to maintain the specific surface area at a high level. It should be as low as possible within the range, and for this reason, the range of 400 to 700 ° C. is preferred. The heat treatment atmosphere may be air or an oxidizing atmosphere, and may be in a nitrogen atmosphere or the like if the oxygen concentration and temperature range for obtaining a perovskite complex oxide.
このようにして，本発明によれば活性金属種を構造中に固溶した比表面積の大きなペロブスカイト型複合酸化物が得られ，このものは還元雰囲気で加熱して活性金属種を表面に析出させた場合に，活性金属種が微細かつ高分散に析出し，高活性で高耐熱な触媒材料となる。 Thus, according to the present invention, a perovskite complex oxide having a large specific surface area in which active metal species are dissolved in the structure is obtained, which is heated in a reducing atmosphere to precipitate the active metal species on the surface. In this case, the active metal species precipitates finely and with high dispersion, resulting in a highly active and heat-resistant catalyst material.
〔参考例１〕
硝酸ランタンと硝酸コバルトを，ランタン元素とコバルト元素のモル比が１：１となるように混合した。この混合物を，ランタン元素とコバルト元素の液中モル濃度がそれぞれ０.２ mol/Lとなるように水に添加して原料溶液を得た。この溶液を攪拌しながら溶液の温度を２５℃に調整し，温度が２５℃に到達した段階で，沈殿剤として炭酸アンモニウム溶液を添加しながらｐＨ＝８に調整した。その後，反応温度を２５℃に保ちながら攪拌を１２時間継続することにより，沈殿の生成を十分進行させた。得られた沈殿を濾過して回収した後，水洗し，１１０℃で乾燥した。得られた粉末を前駆体粉と言う。
[Reference Example 1]
Lanthanum nitrate and cobalt nitrate were mixed so that the molar ratio of the lanthanum element to the cobalt element was 1: 1. This mixture was added to water so that the molar concentrations of lanthanum element and cobalt element in the liquid were each 0.2 mol / L to obtain a raw material solution. While stirring this solution, the temperature of the solution was adjusted to 25 ° C., and when the temperature reached 25 ° C., the pH was adjusted to 8 while adding an ammonium carbonate solution as a precipitant. Thereafter, stirring was continued for 12 hours while maintaining the reaction temperature at 25 ° C., whereby the formation of precipitates was sufficiently advanced. The resulting precipitate was collected by filtration, washed with water, and dried at 110 ° C. The obtained powder is called precursor powder.
得られた前駆体粉の比表面積をＢＥＴ法で測定したところ１０９.０ｍ2/ｇであった。また，この前駆体粉のＸ線粉末回折を行ったところ，図１に示すようにピークが現れないブロードな回折結果となり，非晶質材料であることが確認された。 It was 109.0 m < 2 > / g when the specific surface area of the obtained precursor powder was measured by BET method. Further, when X-ray powder diffraction of this precursor powder was performed, a broad diffraction result in which no peak appeared as shown in FIG. 1 was obtained, and it was confirmed that the precursor powder was an amorphous material.
次に，この前駆体粉を大気雰囲気下で５００℃で熱処理して焼成した。得られた焼成体の比表面積をＢＥＴ法で測定したところ４９.３ｍ2/ｇであった。またＸ線粉末回折では，図１に示すようにＬａＣｏＯ3のペロブスカイト型複合酸化物相であることが確認された。さらに，該前駆体粉に対し，熱処理温度を４００℃，６００℃，７００℃，１０００℃に代えた以外は同様の熱処理を行い，得られた焼成品のＸ線粉末回折の結果を図１に併記した。 Next, the precursor powder was heat-treated at 500 ° C. in an air atmosphere and fired. It was 49.3 m < 2 > / g when the specific surface area of the obtained sintered body was measured by the BET method. X-ray powder diffraction confirmed that it was a LaCoO 3 perovskite complex oxide phase as shown in FIG. Further, the precursor powder was subjected to the same heat treatment except that the heat treatment temperature was changed to 400 ° C., 600 ° C., 700 ° C., and 1000 ° C. The results of X-ray powder diffraction of the obtained fired product are shown in FIG. Also written.
〔実施例１〕
硝酸ランタンと硝酸鉄を，ランタン元素と鉄元素のモル比が１：0.95となるように混合した。この混合物を，ランタン元素と鉄元素の液中モル濃度が合計で 0.2 mol/Lとなるように水を添加して原料溶液を得た。この溶液を攪拌しながら液温を調整し，液温が２５℃に到達した段階で，沈殿剤として炭酸アンモニウム溶液をｐＨ＝１０となるように添加した。その後，反応温度を２５℃に保ちながら攪拌を６時間継続することにより，沈殿の生成を十分進行させた。得られた沈殿を濾過して回収した後，水洗し１１０℃で乾燥した。得られた粉末を前駆体粉と言う。
[Example 1]
Lanthanum nitrate and iron nitrate were mixed so that the molar ratio of lanthanum element to iron element was 1: 0.95. Water was added to this mixture so that the total molar concentration of lanthanum element and iron element was 0.2 mol / L to obtain a raw material solution. The liquid temperature was adjusted while stirring the solution, and when the liquid temperature reached 25 ° C., an ammonium carbonate solution was added as a precipitating agent so that pH = 10. Thereafter, stirring was continued for 6 hours while maintaining the reaction temperature at 25 ° C., so that the precipitation was sufficiently advanced. The resulting precipitate was collected by filtration, washed with water and dried at 110 ° C. The obtained powder is called precursor powder.
この前駆体粉に，前駆体粉を構成しているランタン元素と鉄元素の合計モル数に対して９倍量の硝酸アンモニウムと，ランタン元素と鉄元素とパラジウム元素のモル比が１：0.95：0.05となる量の硝酸パラジウム溶液とを添加混合し，その混合物重量の１０倍量の純水に分散させ，さらにアンモニア水を添加してｐＨ＝１０に調製したスラリーを得た。 In this precursor powder, the molar ratio of ammonium nitrate, lanthanum element, iron element and palladium element, which is 9 times the total number of moles of lanthanum element and iron element constituting the precursor powder, is 1: 0.95: 0.05. An amount of palladium nitrate solution was added and mixed, dispersed in 10 times the amount of pure water, and further added with aqueous ammonia to obtain a slurry adjusted to pH = 10.
このスラリーを１１０℃のオイルバス上のロータリーエバポレーターに入れて１２時間の減圧乾燥を行った。そして，この乾燥品を大気雰囲気下で６００℃で熱処理して焼成した。得られた焼成体の比表面積をＢＥＴ法で測定したところ１９.５ｍ2/ｇであり，またＸ線粉末回折では，図２に示したように，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物相であることが確認された。 This slurry was placed in a rotary evaporator on an oil bath at 110 ° C. and dried under reduced pressure for 12 hours. And this dried product was heat-processed at 600 degreeC by the atmospheric condition, and baked. The specific surface area of the obtained fired body was measured by the BET method to be 19.5 m 2 / g. In X-ray powder diffraction, La (Fe 0.95 Pd 0.05 ) O 3 perovskite as shown in FIG. It was confirmed to be a type complex oxide phase.
次に，添加したパラジウムのうち，このペロブスカイト型複合酸化物中に固溶しているパラジウムの割合 (固溶率) について評価を行った。評価方法には「触媒」Vol.44, 108(2002) に記載されている溶解濃縮法を採用した。この方法によれば，希酸にペロブスカイト複合酸化物を溶解させると，固溶していないパラジウムは酸化パラジウムの形態で残渣として残り，固溶しているパラジウムは溶液中に浸出するため，浸出した貴金属元素イオン濃度からパラジウムの固溶率を評価できるという。この方法に従って本例のペロブスカイト型複合酸化物を評価した結果，パラジウムの固溶率は９５.３％であった。 Next, of the added palladium, the proportion (solid solution rate) of palladium dissolved in the perovskite complex oxide was evaluated. As the evaluation method, the dissolution concentration method described in “Catalyst” Vol. 44, 108 (2002) was adopted. According to this method, when the perovskite complex oxide was dissolved in dilute acid, the undissolved palladium remained as a residue in the form of palladium oxide, and the dissolved palladium was leached into the solution, so that it was leached. The solid solution rate of palladium can be evaluated from the noble metal element ion concentration. As a result of evaluating the perovskite complex oxide of this example according to this method, the solid solution ratio of palladium was 95.3%.
〔実施例２〕
スラリー化のさいに，前駆体粉を構成するランタン元素と鉄元素の合計モル数に対して３倍量の硝酸アンモニウムを混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，図２に併記したように，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１３.７ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は９２.８％であった。
[Example 2]
Example 1 was repeated except that three times the amount of ammonium nitrate was mixed with the total number of moles of lanthanum element and iron element constituting the precursor powder during slurrying. As a result of X-ray powder diffraction of the obtained fired body, as shown in FIG. 2, it is a perovskite type complex oxide of La (Fe 0.95 Pd 0.05 ) O 3 and has a specific surface area of 13.7 m 2 / g. Met. In addition, the solid solution ratio of palladium in this perovskite complex oxide was 92.8%.
〔実施例３〕
硝酸ランタンと硝酸ストロンチウムと硝酸鉄を，ランタン元素とストロンチウム元素と鉄元素のモル比が 0.8： 0.2：0.95となるように混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ0.8Ｓｒ0.2（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１７.２ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は８９.７％であった。
Example 3
Example 1 was repeated except that lanthanum nitrate, strontium nitrate and iron nitrate were mixed so that the molar ratio of lanthanum element, strontium element and iron element was 0.8: 0.2: 0.95. As a result of X-ray powder diffraction of the obtained fired product, it was a perovskite complex oxide of La 0.8 Sr 0.2 (Fe 0.95 Pd 0.05 ) O 3 and a specific surface area was 17.2 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 89.7%.
〔実施例４〕
硝酸ランタンと硝酸コバルトを，ランタン元素とコバルト元素のモル比が１：0.95となるように混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｃｏ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１４.６ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は９５.９％であった。
Example 4
Example 1 was repeated except that lanthanum nitrate and cobalt nitrate were mixed so that the molar ratio of lanthanum element to cobalt element was 1: 0.95. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite complex oxide of La (Co 0.95 Pd 0.05 ) O 3 and a specific surface area was 14.6 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 95.9%.
〔実施例５〕
硝酸ランタンと硝酸マンガンを，ランタン元素とマンガン元素のモル比が１：0.95となるように混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｍｎ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１６.７ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は９９.２％であった。
Example 5
Example 1 was repeated except that lanthanum nitrate and manganese nitrate were mixed so that the molar ratio of lanthanum element to manganese element was 1: 0.95. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite complex oxide of La (Mn 0.95 Pd 0.05 ) O 3 and a specific surface area was 16.7 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 99.2%.
〔比較例１〕
沈殿剤として水酸化ナトリウムを添加しながらｐＨを１２に調整した以外は，実施例１と同様に沈殿を生成させた。得られた沈殿を濾過，水洗，乾燥した。この前駆体粉をペロブスカイト型複合酸化物単相を得るために７００℃で焼成した。他方，熱処理品重量の１０倍量の純水に，ランタン元素と鉄元素とパラジウム元素のモル比が１：0.95：0.05となる量の硝酸パラジウムを溶解し，更にペロブスカイト型複合酸化物が溶解しないようにアンモニア水にてｐＨ＝７に調整した溶液を準備し，この溶液に前記の熱処理品を分散させてスラリーを得た。
[Comparative Example 1]
A precipitate was produced in the same manner as in Example 1 except that the pH was adjusted to 12 while adding sodium hydroxide as a precipitant. The resulting precipitate was filtered, washed with water and dried. This precursor powder was calcined at 700 ° C. in order to obtain a perovskite complex oxide single phase. On the other hand, palladium nitrate in an amount of molar ratio of lanthanum element, iron element and palladium element is 1: 0.95: 0.05 is dissolved in 10 times the amount of heat-treated product, and the perovskite complex oxide is not dissolved. Thus, a solution adjusted to pH = 7 with aqueous ammonia was prepared, and the heat treated product was dispersed in this solution to obtain a slurry.
このスラリーを１１０℃のオイルバス上のロータリーエバポレーターに入れて１２時間の減圧乾燥を行い，得られた乾燥品を大気雰囲気下で６００℃で熱処理して焼成した。得られた焼成体のＸ線粉末回折を行った結果，図３に示したように，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１７.０ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は５７.０％であった。 This slurry was placed in a rotary evaporator on an oil bath at 110 ° C. and dried under reduced pressure for 12 hours. The obtained dried product was heat-treated at 600 ° C. in an air atmosphere and fired. As a result of X-ray powder diffraction of the obtained fired body, as shown in FIG. 3, it is a perovskite type complex oxide of La (Fe 0.95 Pd 0.05 ) O 3 and has a specific surface area of 17.0 m 2 / g. Met. In addition, the solid solution ratio of palladium in this perovskite complex oxide was 57.0%.
〔比較例２〕
硝酸ランタンと硝酸コバルトを，ランタン元素とコバルト元素のモル比が１：0.95となるように混合した以外は，比較例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｃｏ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は２０.５ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は６８.７％であった。
[Comparative Example 2]
Comparative Example 1 was repeated except that lanthanum nitrate and cobalt nitrate were mixed so that the molar ratio of lanthanum element to cobalt element was 1: 0.95. As a result of X-ray powder diffraction of the obtained fired product, it was a perovskite complex oxide of La (Co 0.95 Pd 0.05 ) O 3 and a specific surface area was 20.5 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 68.7%.
〔比較例３〕
硝酸ランタンと硝酸マンガンを，ランタン元素とマンガン元素のモル比が１：0.95となるように混合した以外は，比較例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｍｎ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１４.３ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は６０.９％であった。
[Comparative Example 3]
Comparative Example 1 was repeated except that lanthanum nitrate and manganese nitrate were mixed so that the molar ratio of lanthanum element to manganese element was 1: 0.95. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite type complex oxide of La (Mn 0.95 Pd 0.05 ) O 3 and a specific surface area was 14.3 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 60.9%.
〔比較例４〕
スラリー化のさいに、前駆体粉を構成するランタン元素と鉄元素の合計モル数に対して０．６倍量の硝酸アンモニウムを混合した以外は、実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果、図２に併記したように、Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物に加えてＬａ2ＣＯ5構造の不純物相が生成しており、比表面積は１４．１ｍ2／ｇであった。また、このペロブスカイト型複合酸化物中のパラジウムの固溶率は９９．０％であった。
[Comparative Example 4]
Example 1 was repeated except that 0.6 times the amount of ammonium nitrate was mixed with the total number of moles of lanthanum element and iron element constituting the precursor powder during slurrying. As a result of X-ray powder diffraction of the obtained fired product, as shown in FIG. 2 , the impurity phase of La 2 CO 5 structure was added to the perovskite complex oxide of La (Fe 0.95 Pd 0.05 ) O 3. The specific surface area was 14.1 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 99.0%.
〔比較例５〕
スラリー化のさいに硝酸アンモニウムの添加を行わなかった以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，図２に併記したように，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物に加えてＬａ2ＣＯ5およびＬａ2Ｏ2ＣＯ3構造の不純物相が生成しており，比表面積は１７.６ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は８０.２％であった。
[Comparative Example 5]
Example 1 was repeated except that no ammonium nitrate was added during slurrying. As a result of X-ray powder diffraction of the obtained fired body, as shown in FIG. 2, in addition to the perovskite complex oxide of La (Fe 0.95 Pd 0.05 ) O 3 , La 2 CO 5 and La 2 O 2 An impurity phase having a CO 3 structure was formed, and the specific surface area was 17.6 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 80.2%.
表１は，同じ系統のペロブスカイト型複合酸化物を得た実施例１と比較例１，実施例４と比較例２，実施例５と比較例３の結果を対比して示したものであるが，いずれも比較例に比べて実施例のものでは，同等の比表面積ながら非常に高い貴金属の固溶率を示している。このため，触媒材料として好適である。また，表２には実施例１〜２と比較例４〜５の結果を示したものであるが，前駆体物質を構成する遷移金属元素と希土類元素の合計モル数に対する硝酸イオンおよびアンモニウムイオンの量が０.６倍以下になると，Ｐｄ固溶率は高いものの，Ｌａ2ＣＯ5やＬａ2Ｏ2ＣＯ3などの不純物相が生成することがわかる。この場合には触媒としての機能が低下する。したがって，活性金属種を固溶処理する際に添加する硝酸イオンおよびアンモニウムイオンの量は，前駆体物質を構成する遷移金属元素と希土類元素の合計モル数に対して，０.６倍より大きくするのがよいことがわかる。 Table 1 shows a comparison of the results of Example 1, Comparative Example 1, Example 4, Comparative Example 2, Example 5, and Comparative Example 3 in which perovskite complex oxides of the same system were obtained. In both examples, the solid solution ratio of the noble metal is very high with the same specific surface area as compared with the comparative example. For this reason, it is suitable as a catalyst material. Table 2 shows the results of Examples 1 and 2 and Comparative Examples 4 to 5, but nitrate ions and ammonium ions with respect to the total number of moles of transition metal elements and rare earth elements constituting the precursor material. It can be seen that when the amount is 0.6 times or less, an impurity phase such as La 2 CO 5 or La 2 O 2 CO 3 is formed although the Pd solid solution ratio is high. In this case, the function as a catalyst falls. Therefore, the amount of nitrate ion and ammonium ion to be added when the active metal species is subjected to solid solution treatment is more than 0.6 times the total number of moles of transition metal elements and rare earth elements constituting the precursor material. You can see that it is good.
〔実施例６〕
前駆体粉に, ランタン元素と鉄元素と白金元素のモル比が 1：0.95：0.05となるようにジニトロジアミノ白金を添加混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｆｅ0.95Ｐｔ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１７.３ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中の白金の固溶率は９７.３％であった。
Example 6
Example 1 was repeated except that dinitrodiaminoplatinum was added to and mixed with the precursor powder so that the molar ratio of lanthanum element, iron element and platinum element was 1: 0.95: 0.05. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite complex oxide of La (Fe 0.95 Pt 0.05 ) O 3 and a specific surface area was 17.3 m 2 / g. Further, the solid solution ratio of platinum in the perovskite complex oxide was 97.3%.
〔実施例７〕
前駆体粉に, ランタン元素と鉄元素とロジウム元素のモル比が 1：0.95：0.05となるように硝酸ロジウム溶液を添加混合した以外は，実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｆｅ0.95Ｒｈ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１４.４ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中の白金の固溶率は９２.０％であった。
Example 7
Example 1 was repeated except that the precursor powder was mixed with a rhodium nitrate solution so that the molar ratio of lanthanum element, iron element and rhodium element was 1: 0.95: 0.05. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite complex oxide of La (Fe 0.95 Rh 0.05 ) O 3 and a specific surface area was 14.4 m 2 / g. Further, the solid solution ratio of platinum in the perovskite complex oxide was 92.0%.
〔実施例８〕
前駆体粉の製造時において，沈殿剤として，アンモニア水を添加しながらｐＨを１０に調整したあと，炭酸ガスを９００ｍＬ／ｍｉｎの流量で吹き込んで沈殿を生成させた以外は実施例１を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１５.４ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は９７.１％であった。
Example 8
Example 1 was repeated except that, during the production of the precursor powder, the pH was adjusted to 10 while adding aqueous ammonia as a precipitant, and then carbon dioxide was blown at a flow rate of 900 mL / min to generate a precipitate. . As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite type complex oxide of La (Fe 0.95 Pd 0.05 ) O 3 and a specific surface area was 15.4 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 97.1%.
〔実施例９〕
(1) 沈殿生成後のスラリーに，ランタン元素と鉄元素とパラジウム元素のモル比が 1：0.95：0.05となるように硝酸パラジウムを混合したことと，(2) このスラリーを濾過せずに，そのまま１１０℃のオイルバス上のロータリーエバポレーターに入れて１２時間の減圧乾燥を行ったことの以外は，実施例８を繰り返した。得られた焼成体のＸ線粉末回折を行った結果，Ｌａ（Ｆｅ0.95Ｐｄ0.05）Ｏ3のペロブスカイト型複合酸化物であり，比表面積は１５.８ｍ2/ｇであった。また，このペロブスカイト型複合酸化物中のパラジウムの固溶率は９９.１％であった。
Example 9
(1) The slurry after precipitation was mixed with palladium nitrate so that the molar ratio of lanthanum, iron and palladium was 1: 0.95: 0.05, and (2) without filtering this slurry, Example 8 was repeated except that it was placed in a rotary evaporator on an oil bath at 110 ° C. and dried under reduced pressure for 12 hours. As a result of X-ray powder diffraction of the obtained fired body, it was a perovskite type complex oxide of La (Fe 0.95 Pd 0.05 ) O 3 and a specific surface area was 15.8 m 2 / g. Further, the solid solution ratio of palladium in the perovskite complex oxide was 99.1%.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004061882A JP4729681B2 (en) | 2003-03-28 | 2004-03-05 | Method for producing perovskite complex oxide |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003090080 | 2003-03-28 | ||
| JP2003090080 | 2003-03-28 | ||
| JP2003398453 | 2003-11-28 | ||
| JP2003398453 | 2003-11-28 | ||
| JP2004061882A JP4729681B2 (en) | 2003-03-28 | 2004-03-05 | Method for producing perovskite complex oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2005179168A JP2005179168A (en) | 2005-07-07 |
| JP4729681B2 true JP4729681B2 (en) | 2011-07-20 |
Family
ID=34799255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004061882A Expired - Lifetime JP4729681B2 (en) | 2003-03-28 | 2004-03-05 | Method for producing perovskite complex oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4729681B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5110868B2 (en) * | 2005-12-16 | 2012-12-26 | 北興化学工業株式会社 | Method for producing perovskite complex oxide precursor and method for producing perovskite complex oxide |
| US20140367674A1 (en) * | 2011-11-18 | 2014-12-18 | Japan Science And Technology Agency | Process for forming an amorphous conductive oxide film |
| CN107722022B (en) * | 2016-08-12 | 2020-10-02 | 西安固能新材料科技有限公司 | Compound and preparation method thereof |
| CN112421064B (en) * | 2020-12-03 | 2022-07-12 | 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院) | A2Mn2-xWxO6Perovskite oxide and nitrogen-doped carbon composite catalytic material and preparation method and application thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62269747A (en) * | 1986-05-19 | 1987-11-24 | Toyota Central Res & Dev Lab Inc | Catalyst for purifying exhaust gas |
| JPH05155626A (en) * | 1990-06-21 | 1993-06-22 | Ro Inst Za Hemiju Tehn I Metalurgiju Oour Inst Za Kater I Hemiju Injin | Perovskite matrix and ruthenium perovskite catalyst |
| JPH06100319A (en) * | 1992-09-18 | 1994-04-12 | Toyota Central Res & Dev Lab Inc | Multiple oxide with perovskite structure and its production |
| JPH06106062A (en) * | 1992-02-26 | 1994-04-19 | Daihatsu Motor Co Ltd | Catalyst for purification of exhaust gas and its production |
| JPH07213907A (en) * | 1993-12-10 | 1995-08-15 | Nissan Motor Co Ltd | Exhaust gas purifying catalyst and its production |
| JPH08217461A (en) * | 1995-02-15 | 1996-08-27 | Daihatsu Motor Co Ltd | Production of perovskite type compound oxide |
-
2004
- 2004-03-05 JP JP2004061882A patent/JP4729681B2/en not_active Expired - Lifetime
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62269747A (en) * | 1986-05-19 | 1987-11-24 | Toyota Central Res & Dev Lab Inc | Catalyst for purifying exhaust gas |
| JPH05155626A (en) * | 1990-06-21 | 1993-06-22 | Ro Inst Za Hemiju Tehn I Metalurgiju Oour Inst Za Kater I Hemiju Injin | Perovskite matrix and ruthenium perovskite catalyst |
| JPH06106062A (en) * | 1992-02-26 | 1994-04-19 | Daihatsu Motor Co Ltd | Catalyst for purification of exhaust gas and its production |
| JPH06100319A (en) * | 1992-09-18 | 1994-04-12 | Toyota Central Res & Dev Lab Inc | Multiple oxide with perovskite structure and its production |
| JPH07213907A (en) * | 1993-12-10 | 1995-08-15 | Nissan Motor Co Ltd | Exhaust gas purifying catalyst and its production |
| JPH08217461A (en) * | 1995-02-15 | 1996-08-27 | Daihatsu Motor Co Ltd | Production of perovskite type compound oxide |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2005179168A (en) | 2005-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4755988B2 (en) | Metal oxide solid solution, its production and use | |
| AU2010302213B2 (en) | CeAlO3 perovskites containing transition metal | |
| JP2009507751A (en) | Method for coating metal oxide surface with metal oxide ultrafine particles, and coated body produced therefrom | |
| KR20060046533A (en) | Perovskite complex oxide and catalyst | |
| JP2007084390A (en) | Perovskite type compound oxide particle and its producing method | |
| Megarajan et al. | Improved catalytic activity of PrMO 3 (M= Co and Fe) perovskites: synthesis of thermally stable nanoparticles by a novel hydrothermal method | |
| EP1462427B1 (en) | Method of producing a perovskite mixed oxide | |
| EP1462428A2 (en) | Method of producing perovskite complex oxide and precursor substance used in the method | |
| JP2005111336A (en) | Heat-resistant catalyst and manufacturing method therefor | |
| JP4604211B2 (en) | Perovskite complex oxide, method for producing the same, and catalyst using the same | |
| JP4729681B2 (en) | Method for producing perovskite complex oxide | |
| JP4765094B2 (en) | Method for producing perovskite complex oxide | |
| JP4768475B2 (en) | Composite oxide and filter for PM combustion catalyst | |
| EP1928788B1 (en) | Method for preparing metal oxide containing precious metals | |
| EP3384985A1 (en) | Steam reforming catalyst for hydrocarbons | |
| WO2020217830A1 (en) | Method for producing rare earth element-containing titanium hydroxide and titanium dioxide | |
| JP4204487B2 (en) | Exhaust gas purification catalyst, production method thereof, and exhaust gas purification catalyst device for vehicle | |
| JP2018104230A (en) | Method for producing perovskite composite oxide | |
| KR101922193B1 (en) | Hollow nanoreactor comprising supported metal catalysts inside the cavity and manufacturing method thereof | |
| JP3752529B2 (en) | Iridium support material, iridium support method, and iridium support catalyst | |
| US6210649B1 (en) | Metal oxide catalysts for nitric oxide reduction | |
| JP4848554B2 (en) | Production method of perovskite complex oxide with pore distribution with high catalytic activity | |
| JP2004043282A (en) | Method of manufacturing titanium oxide | |
| JP2006012764A (en) | Material for electrode of solid electrolyte type fuel cell and electrode | |
| KR100411493B1 (en) | A fine particles of Nickel and the method of processing thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070228 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20090223 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100406 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100603 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20101130 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110126 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110222 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20110316 |
|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20110316 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110316 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20110316 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140428 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 4729681 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |