Acta Phys. -Chim. Sin. ›› 1993, Vol. 9 ›› Issue (02): 187-192.doi: 10.3866/PKU.WHXB19930209

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Study on Dispersion of V2O5 on Surface of SiO2 and the Effect of Promoter K2SO4

Zhao Bi-Ying; Wang Qiu-Xia; Tang You-Qi   

  1. Institute of Physical Chemistry, Peking University, Beijing 100871
  • Received:1991-11-11 Revised:1992-05-16 Published:1993-04-15
  • Contact: Zhao Bi-Ying

Abstract: It has been shown by in situ XRD that V_2O_5 can disperse spontaneously onto the 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, The dispersion process of V_2O_5 onto the surface of silica gel can be accelerated by using K_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 one of the important reasons why K_2SO_4 can improve the selectivity of V_2O_5/SiO_2 for many selective oxidations.

Key words: V2O5/SiO2 catalyst, Dispersion on surface, K2SO4 promoter