Hydrogen assisted oxygen desorption from the V2O5(010) surface

Vanadium oxide surfaces are well known to play an active role as catalysts in hydrocarbon oxidation reactions where oxygen from different surface site s participates in the reaction. Due to the ubiquity of hydrogen in these sy stems, reaction steps involving (temporary) hydrogenation are possible and may influence the overall reaction scheme. This work examines structural an d energetic consequences of hydrogen interacting with different oxygen site s at the V2O5(010) surface where the local surface environment is modeled b y embedded clusters. The electronic structure and equilibrium geometries of the clusters are obtained by density functional theory (DFT) using gradien t corrected functionals (RPBE) for exchange and correlation. Hydrogen is fo und to stabilize preferentially near oxygen sites forming surface OH and H2 O species with binding energies of 0.5-2.3 eV per H atom depending on the s ite and species. Hydrogen adsorption weakens the binding of the surface oxy gen with its vanadium neighbors considerably where the weakening is larger for H2O than for OH formation as evidenced by bond order analyses and resul ts of the binding energetics. Thus, the studies suggest strongly that the p resence of hydrogen at the oxide surface facilitates oxygen removal and, th erefore, contributes to the enhanced yield of oxygenated products near vana dia based surfaces.