Restructuring of silica supported vanadia during propane oxidative dehydrogenation studied by combined synchrotron radiation based in situ soft X-ray absorption and photoemission

Abstract

A series of vanadia catalysts supported on mesoporous silica SBA-15 has been prepared with a loading in the range of 2–14 wt-% V and characterized under oxygen and propane oxidative dehydrogenation reaction conditions at elevated temperature up to 550 °C. In situ soft X-ray absorption spectra at the vanadium L- and oxygen K-edges and in situ synchrotron based X-ray photoemission spectra reveal a restructuring of vanadium species that results in an enhanced degree of dispersion of molecular vanadia species on the silica support. The impact of the X-ray beam on the XAS spectra of dispersed VxOy species has been studied and a brief perspective of X-ray based electron spectroscopy as a probe in catalyst characterization is given.