【摘要】 在XRD相定量分析的阈值时,MoO₃/TiO₂（锐钛矿）界面上,MoO₃和TiO₂都有一个单分子层左右的非晶相分散,当MoO₃在催化剂中的含量超过阈值时,则它的非晶相量将增加为该含量的（1—0.73）倍。在这个非晶相层中,主要是聚钼酸和少量的MoO₃集合体,TiO₂则是表面层结构的畸变,它们的红外特征是:Mo=O的伸缩振动由993cm^-1红移到960cm^-1,MoO₃集合体的伸缩振动为828cm^-1,未发现MoO₄^-2的伸缩振动(898cm^-1),766和603cm^-1是畸变的TiO₂表面层同含Mo物种形成的表面化学键的特征伸缩振动,这个表面化学键对邻二甲苯选择氧化有利。更多还原

【Abstract】 The dispersion capacity of MoO3 and TiO2 at the interface of MoO3/ TiO2 calcined at 500℃ for 5 h was studied by XRD and FT-IR difference spectra. There is about one monolayer of non-crystalline phase of MoO3 and TiO2 at the interface. When MoO3 content is higher than the threshold value, the amount of non-crystalline phase of MoO3 increases to (1-0.73) times of MoO3 content. The predominant species in the layer of non-crystalline phase are polymolybdate, MoO3 cluster and the distorted crystal lattice of octahedral TiO6 of TiO2 .The stretching vibration of Mo = O of polymolybdate shifts to red from 993 to 960 cm-1, the stretching vibration of MoO3 cluster is found at 828 cm-1, and the stretching vibration of adsorbed Mo-O-Ti band is found at 766 and 603 cm-1. The formation of chemical bond between TiO2 and MoO3 at the interface is favorable to the selective oxidation of o-xylene.更多还原