Comparative DFT+U and HSE Study of the Oxygen Evolution Electrocatalysis on Perovskite Oxides

Abstract

The most common method for incorporating strong electron correlations is either to apply the Hubbard U correction on top of standard density functional theory calculations (DFT) or to use hybrid functionals. In this study, we elucidate the sensitivity of the Hubbard U correction in the PBE+U functional and the amount of exact exchange, α, in the hybrid HSE functional on the structural stability, catalytic activity, and electronic conductivity of pure and doped perovskite oxides, ABO3 (A = La, Ca, Sr, and Ba; B = Cr, Mn, Fe, Co, Ni, and Cu) for oxygen evolution electrocatalysis. We find a strong dependence of heat of formations and reaction overpotentials for a range of U = 0, 3, and 5 eV and α = 0, 0.15, 0.25, and 0.35 values investigated in this study, which we attribute primarily to changes in the oxidation state of B cations. If the valence of B cations in the perovskite and reference oxide is the same, then the U and α dependences are very small. However, if the valences are different then heat of for...