Freeing the Surface-Bound Excitons to Facilitate Water Oxidation Catalysis in BiVO4 Photoanode

Illuminating the charge transport at photoanode-electrolyte interface is pivotal for optimizing photoelectrochemical (PEC) water oxidation performance of BiVO4. Our study demonstrates a preferentially photogenerated electrons trapping process at BiVO4 surface, followed by the formation of surface-bound excitons. A facile LSV treatment method is described, which remarkably passivate the surface electron trapping states by the formation surface oxygen vacancies. The surface oxygen vacancies could “free” the photogenerated holes from the surface-bound excitons. As a result, more photogenerated holes are available on BiVO4 surface and the PEC performance is enhanced.