Role of Te on selective oxidation of propane to acrolein over MoBiTeO/SiO2 catalysts

A series of MoBiTeO/SiO2 catalysts with different Te contents was prepared by impregnation method. Effect of Te on the catalysts'structure, acidity and catalytic performance for selective oxidation of propane to acrolem was investigated by XRD, Raman, XPS, NH3-TPD, FIF-IR, and performance evaluation techniques. The results indicated that by forming Mo-O-Te bond with the Mo species, tellurium component in the catalyst improved the dispersion of Mo oxide species that would be favorable to the formation of isolate active sites on the catalysts. Besides, Te could be the centers for alpha-H abstraction of propene and O-insertion to allyl species. So, the addition of Te to MoBiO/SiO2 catalyst promoted the acrolem selectivity greatly. However, the addition of tellurium also could contribute the formation of B acid sites in MoBiTeO/SiO2 catalysts that had been proved to be harmful to the generation of acrolein. Therefore, there existed an optimal scale for the amount of Te-content in the MoBiTeO/SiO, catalysts. When the n(Te)/n(Mb) ratio was 0.05-0.1, the catalyst showed the best catalytic performance.