Reactivity of lattice oxygens present in V₂O₅(010): A periodic first-principles investigation

The present paper deals with the periodic first-principles density functional (DFT) calculations on hydrogen adsorption on the V₂O₅(010) surface. The calculated results reveal that the vanadyl oxygen is the most active site for hydrogen adsorption among the three kinds of structurally different lattice oxygens in terms of their coordination with vanadiums. Our calculated harmonic vibrational frequencies of the three types of OH species are found to correlate with their corresponding bond strengths and support their respective reactivity. It is confirmed that the lattice relaxation contributes to the reactivity of the oxygens significantly in all cases while the local environment of adsorption site affects both the geometry and reactivity of the adsorption system only in the case of tricoordinated oxygen. Hydrogen adsorption at these oxygens reduces the surface in different ways. Comparison of the desorption ability of the OH species from the surface shows that removal of the O₁H species, formed by H adsorption at vanadyl oxygen, is energetically preferable. The present work demonstrates that the periodic approach gets rid of the artifacts of the cluster method, and thus, first-principles DFT methodology demonstrates its reliability to investigate geometric, electronic, and catalytic properties of transition metal oxide catalysts.