In situ FTIR and Raman Study on the Distribution and Reactivity of Surface Vanadia Species in V2O5/CeO2 Catalysts

Abstract

The surface structure and reactivity of vanadia supported on ceria catalysts were studied by Ramanspectroscopy and methanol adsorption and temperature-programmed surface reaction (TPRS) of theadsorbed species monitored in situ by infrared spectroscopy. Monomeric and polymeric vanadia surfacespecies and CeVO4were identified on the catalysts. Methanol adsorption reveled that mostly reducedCe3+sites are present in the surface of the catalysts, produced as a result of the reductive solid reaction ofVOxspecies with the ceria surface. Adsorbed methanol/methoxy decomposed stepwise to formate and,finally, carbonate/carbon dioxide. The reactivity is linked to interphase sites, Ce–O–V, which could favorthe abstraction of hydrogen during the methoxy transformation to formates.