Supported two- and three-dimensional vanadium oxide species on the surface of β-SiC

Abstract

A series of supported two- and three-dimensional vanadium oxide surface species on β-SiC with various V coverages are prepared via incipient wetness impregnation and characterized by a variety of ex and in situ techniques. The oxidative dehydrogenation of propane (ODHP) is also used as a probe reaction to complementarily distinguish between two- and three-dimensional VO_x surface species. Herein, we show that treating pristine β-SiC with oxygen transforms the existing amorphous SiO_xC_y surface layer into a more SiO₂-type layer, though with a negligible formation of Si–OH sites, which initially were expected to be the anchor sites for VO_x species. In its place, the C–OH functional groups identified by X-ray photoelectron spectroscopy (XPS) act as anchor sites for the VO_x species during the impregnation process, and are consumed as a function of V coverage. Our experimental observations all corroborate the formation of two- and three-dimensional VO_x species on the surface of β-SiC.