α-Bi_2Mo_3O_(12)/MoO_3催化剂的表面光电压谱研究

Studies of Surface Photovoltage Spectra on a - Bi2Mo3O12/MoO3 Catalysts

合成了系列催化剂Bi_xPMo_(12)O_y(2=2～9,y=43～64),高温焙烧后该系列催化剂的基本组成为白钨矿型的α—Bi_2Mo_3O_(12)/MoO_3.研究其表面光电压谱发现,随着Bi/P比的增高,相应的光电压响应呈现规律性变化.在该系列催化剂上的丙烷选择氧化实验结果表明,铋含量增加,催化剂中作为碱性位的阳离子缺陷的浓度随着白钨矿结构中阳离子空位的有序化而下降,反映在光电压响应中对应着P_1带强度的减弱和P_2带的负移,而与之对应的催化活性迅速下降.

A series of catalysts,BixPMo12Oy(x =2~9,y = 43~64) ,was synthesized from 12 -molybdophosphoric acid in acidic condition. The results indicated that the basic composition of the calcinated catalysts was a - Bi2Mo3O12/MoO3. It was found that with the increase of Bi/P molar ratio, the surface photovoltage spectra (SPS) of the catalysts exhibits regular evolutions characteristic. Another experiments using the samples as catalysts in selective oxidation of propane showed that the content of Bi increased, the amount of cation - flaw as basic capacity in the catalysts decreaed with the A vacancy in scheelite - type oxides (AMO4) distribution in order. Correspondingly, the shift of P2 band to negative electric field and decreased of P1 band, the activity of catalytic decrease,rapidly.