In situ FTIR and Raman study on the distribution and reactivity of surface vanadia species in V2O5/CeO2 catalysts

• We studied vanadia-ceria catalysts in situ by Raman and infrared spectroscopies.
• Solid reaction produces CeVO4 surface species.
• Methanol adsorbs mainly on reduced Ce3+ sites.
• Methoxy decomposes to formate on interphase Ce–O–V sites.

The surface structure and reactivity of vanadia supported on ceria catalysts were studied by Raman spectroscopy and methanol adsorption and temperature-programmed surface reaction (TPRS) of the adsorbed species monitored in situ by infrared spectroscopy. Monomeric and polymeric vanadia surface species and CeVO4 were identified on the catalysts. Methanol adsorption reveled that mostly reduced Ce3+ sites are present in the surface of the catalysts, produced as a result of the reductive solid reaction of VOx species 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 favor the abstraction of hydrogen during the methoxy transformation to formates.

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