FTIR studies of the interaction of aromatic hydrocarbons with vanadium oxide layered on ZrO2 and TiO2

Abstract

The reactivities of toluene, m-xylene, phenol and benzene on mono- and multi-layer V/Ti and V/Zr oxides prepared by the gas-phase method have been studied by FTIR spectroscopy. It is found that Lewis-acidic sites (vanadium ion) play an important role in the formation of π-complexes of toluene, m-xylene and benzene. The methyl group of the π-complex is dehydrogenated by the VO species to form benzyl species and benzaldehyde. On the other hand, phenol is adsorbed via its oxygen with its benzene ring oriented perpendicular to the surface. From spectral similarities, it is concluded that benzene is adsorbed to form mono- and/or disubstituted species. The activity of VO species on the monolayer catalyst is higher than that on the multilayer catalyst.