Effect of Rh Doping on Optical Absorption and Oxygen Evolution Reaction Activity on BaTiO (001) Surfaces.

In the present work, we investigate the potential of modified barium titanate (BaTiO), an inexpensive perovskite oxide derived from earth-abundant precursors, for developing efficient water oxidation electrocatalysts using first-principles calculations. Based on our calculations, Rh doping is a way of making BaTiO absorb more light and have less overpotential needed for water to oxidize. It has been shown that a TiO-terminated BaTiO (001) surface is more promising from the point of view of its use as a catalyst. Rh doping expands the spectrum of absorbed light to the entire visible range. The aqueous environment significantly affects the ability of Rh-doped BaTiO to absorb solar radiation. After Ti→Rh replacement, the doping ion can take over part of the electron density from neighboring oxygen ions. As a result, during the water oxidation reaction, rhodium ions can be in an intermediate oxidation state between 3+ and 4+. This affects the adsorption energy of reaction intermediates on the catalyst's surface, reducing the overpotential value.