Bi-Mo-Nb复合氧化物的结构与对丙烯氧化的催化活性

本文用XRD, IR, Raman, SEM和ESR等方法研究了系列氧化物Bi~2Mo~3-3XNb~2xO~12-4X(X=0.00, 0.02, 0.05, 0.10, 0.15, 0.20, 0.25) 的结构和对丙烯氧化的催化活性。结果表明, 在X<0.25范围内, 催化剂基本保持典型的α-Bi~2Mo~3O~12结构, 少量Nb^5+的掺杂, 可取代晶格中的Mo^6+, 产生氧空位,无序分布的氧空位的浓度先随X值的增加而增加, 当X=0.15时达到最大值, 催化剂对丙烯氧化的催化活性与这种氧空位的浓度成正比, 反应遵循Redox机理。

Structure and catalytic activity for propylene oxidation of Bi-Mo-Nb complex oxide catalysts

The structure and catalytic activity for propylene oxidation of series oxides Bi2Mo3-3x-Nb2xO12-4x (X=0.00, 0.02, 0.05, 0.10, 0.15, 0.20, 0.25) have been studied by means of XRD, IR, Raman, SEM, ESR, etc. The results showed that in the range of X < 0.25 the catalysts possessed a typical a-Bi2Mo3O12 structure, while the oxygen vacancies were formed due to the substitution of Nb5+ for Mo6+, and the concentration of randomly distributed oxygen vacancy passed through a max. at X = 0.15. The catalytic activity was in parallel with the concentration of oxygen vacancy. The catalytic reaction obeyed redox mechanism.