摘要
用原位XRD方法证明V_2O_5能在硅胶表面自发分散,但所需温度较高.水汽对V_2O_6的分散有一定的阻碍作用.K_2SO_4可显著加快V_2O_5在SiO_2表面的分散速度,并能降低V_2O_5/SiO_2的表面酸性.被中和的主要是强酸位.这可能是K_2SO_4能够改善V_2O_5/SiO_2催化剂在选择氧化反应中选择性的重要原因之一.
It has been shown by in situ XRD that V_2O_5 can disperse spontaneously ontothe surface of silica gel,but the dispersion temperature is relatively high.The presence of H_2O vapour inhibits the dispersion of V_2O_5 to a certain extent,Thedispersion process of V_2O_5 onto the surface of silica gel can be accelerated by usingK_2SO_4 as an additive.The surface acidity of V_2O_5/SiO_2 is quite strong.However,K_2SO_4 can suppress the acidity by neutralizing strong acid sites.This may be oneof the important reasons why K_2SO_4 can improve the selectivity of V_2O_5/SiO_2 formany selective oxidations.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1993年第2期187-192,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金
关键词
王氧化二钒
催化剂
表面分散
V_2O_5/SiO_2 catalyst
Dispersion on surface
K_2SO_4 promoter