This paper reports an X-ray photoemission study (XPS) of the core levels and the valence band of vanadia-titania catalysts and their precursor oxides. The XPS spectra of the vanadium core levels indicate that surface vanadium atoms are present with different oxidation states. Furthermore, it is demonstrated, for the first time, that the electronic states observed in the XPS valence-band spectra between the Fermi edge and the O 2p bands have mainly a V 3d character.

This paper reports an X-ray photoemission study (XPS) of the core levels and the valence band of vanadia-titania catalysts and their precursor oxides. The XPS spectra of the vanadium core levels indicate that surface vanadium atoms are present with different oxidation states. Furthermore, it is demonstrated, for the first time, that the electronic states observed in the XPS valence-band spectra between the Fermi edge and the O 2p bands have mainly a V 3d character.