A Study of Catalyst Design by Use of Molecular or Crystalline Mixed Oxides

尝试了基于分子或晶体混合氧化物的催化剂设计。通过对杂多化合物、钙钛矿型复合氧化物和V-P氧化物的研究，阐明了反应机理和反应物与活性中心之间的相互作用。并研究了它们的薄膜和超细粒子的形成对催化性能的影响。(1)假液相的原位测量用FT-IR和固体NMR分析了假液相中分子的化学位移。质子化的乙醇单体、二聚体和乙氧基是脱水反应的重要中间体，可通过^1H和13 C NMR直接检测<13>到。原位FT-IR测量支持这些物种的存在。设计了醛选择氧化催化剂。通过碱取代H^+来控制酸性，通过V部分取代Mo（多原子）来提高氧化能力，这对选择性催化剂的设计是有效的。(2)用XPS、TEM、SEM、EDX和NO吸附等手段对催化燃烧活性较高的LaCoO_3/ZrO_2催化剂的表面结构进行了表征。结果表明，LaCoO_3等单层薄膜均匀地覆盖在ZrO_2表面。(3)V-P氧化物形貌的控制研究了丁烷选择氧化制顺酐的高效催化剂（VO）_2P_2O_7的形貌对催化剂性能的影响。结果表明，在工作条件下，沿[020]方向生长的大晶粒具有较高的选择性和稳定性。

Catalyst design based on molecular or crystalline mixed oxides was attempted. Heteropoly compounds, perovskite-type mixed oxides and V-P oxides were examined for this purpose by elucidating reaction mechanism and the interaction between reactants and the active sites under the working conditions. Furthermore, the effects of the formation of their thin films and ultrafine particles on the catalytic performance were studied.(1) In situ measurement of pseudoliquid phase Chemical shifts of molecules in the pseudoliquid phase was analyzed by FT-IR and solid state NMR. Protonated ethanol monomer, dimer, and ethoxy group, which are important intermediates for the dehydration, were directly detected by ^1H and ^<13>C NMR. In situ FT-IR measurement supports the presence of these species. Catalyst for selective oxidation of aldehyde was designed. Control of acidity by substitution of alkali for H^+ and increase of oxidation ability by partial substitution of V for Mo (polyatom) were found to be effective for the design of selective catalyst.(2) Catalytic properties of thin films of perovskites The surface structure of LaCoO_3/ZrO_2, which was highly active for catalytic combustion, was characterized by XPS, TEM, SEM, EDX, and NO adsorption. It was shown that monolayer thin film of LaCoO_3 or the like covered uniformly the surface of ZrO_2.(3) Control of morphology of V-P-oxides The effect of morphology of (VO)_2P_2O_7, which is efficient catalyst for the selective oxidation of butane to maleic anhydride, was studied. It was concluded that large crystallites grown in the direction of [020] was high selective and was stable under the working conditions.