Improvement of BiVO4 Photoanode Performance During Water Photo-Oxidation Using Rh-Doped SrTiO3 Perovskite as a Co-Catalyst

In this work, a water splitting photoanode composed of a BiVO4 thin film surface modified by the deposition of a rhodium (Rh)-doped SrTiO3 perovskite is fabricated, and the Rh-doped SrTiO3 outer layer exhibits special photoelectrochemical (PEC) oxygen evolution co-catalytic activity. Controlled intensity modulated photo-current spectroscopy, electrochemical impedance spectroscopy, and other electrochemical results indicate that the Rh on the perovskite provide an oxidation active site during the PEC water oxidation process by reducing the reaction energy barrier for water oxidation. Theoretical calculations indicate that the water oxidation reaction is more likely to occur on the (110) crystal plane of Rh-SrTiO3 because the oxygen evolution reaction overpotential on the (110) crystal plane is reduced significantly. Therefore, the obtained BiVO4/Rh5%-SrTiO3 photoanode exhibits an optimized PEC performance. In particular, it facilitates the saturation of the photocurrent density. Thus, the presence of doped Rh in SrTiO3 can reduce the amount of noble metals required while achieving excellent and stable oxygen evolution properties.