Photoelectrodeposition of Ag3PO4 nanoparticles on BiVO4 photoanode for enhancing its photoelectrochemical water oxidation performance

Bismuth vanadate (BiVO4) has emerged as one of the most promising materials that can be used for the fabrication of solar-driven water splitting photoanodes. However, its photocatalytic activity is limited by the low charge carriers’ mobility, fast charge carrier recombination, and the slow kinetics of the water oxidation reaction. In this study, silver phosphate nanoparticles (Ag3PO4 NPs) are decorated on the BiVO4 surface via a facile photodeposition of Ag NPs, which are subsequently oxidized into Ag3PO4 NPs by a photoelectrochemical oxidation process. We demonstrate that Ag3PO4 NPs play as a passivator to reduce the charge carrier recombination on the BiVO4 surface and to accelerate the water oxidation reaction at the BiVO4/electrolyte interface. The best BiVO4/Ag3PO4 photoanode generates a photocatalytic current density of ca. 4.1 mA/cm2 when it is operated at 1.23 V vs. RHE in a pH 7 phosphate electrolyte and under 1 sun illumination. This photocatalytic performance is more than twice compared to that obtained for the pristine BiVO4 photoanode.