Molybdenum role: Mo-Sm-V-O catalytic system for propane oxidative dehydrogenation Original Research Article

SmVO4-impregnated molybdenum oxide catalysts have been prepared with different molybdenum amounts to obtain surface coverages below and above the theoretical monolayer. The physicochemical properties of the catalysts were characterized by BET specific surface area measurements, X-ray diffraction (XRD), temperature-programmed reduction (TPR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). At low molybdenum loading (surface coverage below the theoretical monolayer), surface molybdenum oxide species were detected by Raman. TPR and XPS techniques were used to investigate the reducibility of this species. The results suggest that a strong molybdenum–SmVO4 interaction exist. At higher molybdenum loadings (exceeding the monolayer coverage), crystalline MoO3 is formed. The catalytic behavior was evaluated in the propane oxidative dehydrogenation (ODH). The incorporation of low molybdenum loading results in an increase of the selectivity to propene. The highest yield to propene was obtained on SmVO4-impregnated with 3 mol% Mo. The performance of SmVO4-impregnated molybdenum oxide catalysts was compared with that of SmVO4-impregnated vanadium oxide catalysts.