摘要
研究了V-Ti体系中TiO_2晶体结构与催化活性的联系,本系统中,当焙烧温度超过650℃,由于TiO_2由锐钛矿型转变为金红石型,使催化活性降低。助剂作用的ESCA、XRD、LRS研究表明,与通常V-Ti系催化剂不同,本催化剂由于助剂的作用,使V=O键减弱而利于活化;且随K助剂含量增加,V_2O_(4.33)晶胞的001面取向优化加强,更宜于催化活性的充分显示。
The effect of crystal structure of TiO_2 on the catalytic oxidation activities was studied. In this system, when the calcination temperature was above 650℃, TiO_2 changed from anatase to rutile, which caused the decrease of catalytic activity.The study of ESCA, XRD and LRS indicated that promoters in the catalyst weakened the V=O bond strength in favour of the activation ot the V=O bond; The increase of the amount of potassium as promotor resulted in the intensification of the preferred orientation of (001) crystal face in V_2O_(4.33) crystal cell.
关键词
氧化
二甲苯
苯酐
催化剂
钾
xylene
phthalic anhydride
catalyst
oxidation
vanadium oxide
potassium
