LAUSR

We present a study of the effects of oxygen vacancies (Ovac) on the oxygen evolution reaction (OER) on the TiO2-terminated (001) surface of cubic BaTiO3 (cBTO-TiO2) using spin-polarized DFT+U calculations and the standard (cation-based) four proton-coupled-electron-transfer methodology. We find that the excess electrons associated with Ovac’s are involved in charge transfer (CT) to the intermediate adsorbate species HO*, O*, and HOO* and/or new surface oxygen hole states that we identified. The CT is responsible for an increase in these species’ binding energies to the oxygen-deficient surface (cBTO-TiO2–x) to an extent consistent with their electronegativity. The much stronger stabilization of HO* and O* compared to HOO* results in an increased overpotential ηOER on the reduced oxide. This result is at odds with experiment that shows a significantly increased efficiency for oxygen-deficient BTO, suggesting that a different mechanism and/or surface must be involved under the experimental conditions. We al...