Effect of WO3 in mixed V2O5-WO3/ZrO2 catalysts on their surface structures and decomposition of propan-2-ol

V2O5-WO3/ZrO2 catalysts prepared by a two-step impregnation method have been studied by FTIR and laser-Raman spectrometry together with a pulse method. Addition of WO3 to 2 wt.% V2O5/ZrO2 catalyst increased the activity of propan-2-ol decomposition and the selectivity for propene. On 5 wt.% V2O5/ZrO2 catalyst the activity was hardly affected but the selectivity for propene was increased by the additive. From the FTIR bands in the region of 1100-900 cm(-1), when WO3 was added to V2O5/ZrO2 catalysts, the tungsten oxide species was well dispersed on the zirconia support and directly interacted with zirconia to form the bridging layer(s) between the support and vanadate species. Thus, the addition of WO3, caused the reconstruction of the surface vanadate species. As a result, the surface acidity as well as the catalytic activity changed with the amount of WO3,.