Oxygen 1s NEXAFS spectra of the V2O5(010) surface: theoretical studies using ab initio DFT cluster models

Abstract

The (010) surface of vanadium pentoxide, V2O5, contains 1-, 2-, and 3-fold coordinated oxygen centers which can participate as active sites in specific surface reactions. In the present work we use ab initio density functional theory DFT together with cluster models to calculate 1s core excitation spectra of the different oxygen centers. Excitation energies and intensities are characterized by details of local V–O binding where the data depend strongly on coordination. As a result, strong coordination dependence of the angle-resolved NEXAFS spectra of different oxygen centers is found. The differences can also be seen in the total spectrum obtained from a superposition of the atom specific spectra. A comparison of our theoretical spectra with experimental NEXAFS data yields good agreement and allows an assignment of the experimental peaks to the differently coordinated oxygen centers.