BiMo基复合氧化物催化剂晶格氧性质与丙烷选择氧化性能

研究了不同组成、结构的BiMo基复合氧化物催化剂的丙烷选择氧化至丙烯醛的性能.X射线衍射(XRD)、X光电子能谱(XPS)、原位傅里叶变换激光拉曼光谱(FT-LRS)、电子顺磁共振(ESR)等多种表征结果表明,BiMo基复合氧化物催化剂上丙烷经由中间物丙烯选择氧化至丙烯醛,催化剂的晶格氧为选择性活性氧物种.丙烷直接氧化下丙烷至丙烯醛的选择性和收率与催化剂的Mo=O物种的氧化-还原性质密切关联,而Mo=O物种的性质又取决于Mo离子的配位环境,Mo=O物种的选择性转化丙烷经由丙烯至丙烯醛活性随畸变MoO6八面体、共顶点八面体、共边八面体、MoO4四面体配位环境递增.组成、结构优化调变的催化剂上丙烷选择氧化至丙烯醛选择性和收率可达45%和13.5%,催化剂中具有选择氧化活性的晶格氧物种数可达258 μmol/g.

Lattice oxygen properties of BiMo based catalysts for selective oxidation of propane to acrolein

The properties of BiMo based catalysts with varied composition and structure for the direct selective oxidation of propane to acrolein were investigated. It has been seen by XRD, XPS, in situ FT-LRS, and ESR that propane is selectively oxidized to acrolein via propylene intermediate species. The lattice oxygen of the catalysts is the active oxygen species for the selective oxidation of propane to acrolein via propylene; the selectivity and yield of acrolein associate closely with the redox properties of Mo=O species while the activity of Mo=O correlates tightly with its coordinated circumstance. The selective activity of Mo=O is improved in a sequence of locations as distorted octahedral MoO₆, corner shared octahedral in koechlinite structure, edge shared octahedral and tetrahedral MoO₄ in distorted scheelite structure. The selectivity and yield of acrolein approached 45mol% and 13.5mol%, respectively, and the amount of lattice oxygen with selective oxidative activity amounted to 258 mol/g on the optimum catalyst.