Catalytic Performance and Characterization of VTeO/SiO_2 Catalysts for Selective Oxidation of Propane to Acrolein

The structures and catalytic performances of VTeO/SiO_2 catalysts for selective oxidation of propane to acrolein were studied by XRD,TPR,Raman and XPS techniques.Under the reaction conditions studied,3V/SiO_2 catalyst showed a high activity for propane conversion,but the products were mainly C_3H_6 and CO_x.With addition of Te to the catalyst,conversion of propane and selectivities to C_3H_6 and CO_x were decreased,whereas the selectivity to acrolein was notably increased.The maximal yield of acrolein of 6.6% was obtained on 3V0.5Te/SiO_2 catalyst under 520℃.XPS results indicated that the VTeO/SiO_2,VO_x/SiO_2 and TeOx/SiO_2 catalysts were identical in oxidation states of V~(5+) and Te~(4+),but the catalysts were distinctly different in their structures,as demonstrated by the results of XRD,TPR and Raman.Due to the interaction between V and Te,VTeO/SiO_2 catalysts presented higher dispersion of both V and Te oxides.On the catalysts,amorphous structures were formed by highly dispersed structural units,[Te_2O_5] groups,as well as vanadate-and/or polyvadate-like species.Considering the high dispersion of the active sites in the disorder structures,the structures were assumed to be beneficial to the formation of acrolein from propane oxidation.