Surface-copper-doped WO3 photoanode for photoelectrochemical water splitting

Surface Cu2+ dopants on WO3 photoanodes were created with a facile hydrothermal method for photoelectrochemical water splitting. The introduction of Cu2+ ions was demonstrated to significantly improve the interface charge transfer efficiency of WO3. Furthermore, the surface Cu2+ ions also acted as adsorption and activation sites for intermediate species, decreasing Gibbs free energy and thus enhancing the oxygen evolution reaction activity. Consequently, incident-photon-to-current-conversion efficiency was increased by 600% under the irradiation of 340 nm monochromatic light and 1.23 V (vs reversible hydrogen electrode) bias.