负载型Nb2O5催化剂中的载体效应

采用草酸铌水溶液浸渍法将Nb2O5负载于锐钛矿相TiO2 （A-TiO2）、四方相ZrO2（t-ZrO2）、γ-Al2O3和SiO2表面.对于多晶载体,采用x-射线相定量分析技术与“嵌入模型”理论分析能获得一致的单层分散容量,但因多晶载体表面空位密度与结构不同,“嵌入模型”难以分析分散物种NbOx在载体表面的聚集行为.而在非晶载体SiO2表面,Nb2O5的负载过程更适合采用“羟基滴定模型”,NbOx物种在载体表面分散与集聚同时进行.载体在Nb2O5负载过程中呈现较强的载体效应.

The Carrier Effect for Supported Nb2O5 Catalysts

Supported Nb2O5 samples were prepared by incipient wetness impregnation TiO2, t-ZrO2, and γ-Al2O3 and SiO2 with a- queous solutions of niobium oxalate. For the support with polycrystalline structure, there is an almost identical ＂dispersion capaci- ty＂ obtained by the X-ray quantitative phase analysis technology and the ＂incorporated model＂ theoretical analysis. However, it is difficult to describe the aggregation behavior on the surface of polycrystalline support with different vacancy density and structure by using the ＂incorporated model＂. For amorphous SiO2 support, the dispersion process of Nb2 O5 would be described by ＂hydrox- yl titration model＂. In the dispersion process of Nb2O5, a significant carrier effect was observed.