Enhanced photoelectrochemical performance of nanoporous BiVO4 photoanode by combining surface deposited cobalt-phosphate with hydrogenation treatment

Abstract Improving charge transportation and interfacial charge transfer in semiconductor photoelectrodes are two critical issues for achieving high-efficiency photoelectrochemical (PEC) water splitting. Herein, a combined hydrogenation treatment and cobalt-phosphate (Co-Pi) deposition is reported to dramatically enhance the PEC performance of nanoporous BiVO 4 photoanode. Linear sweep voltammograms show that after the combined treatment, photocurrent density of nanoporous BiVO 4 photoanode is increased for ca. 3 times at 1.23 V versus reversible hydrogen electrode (RHE), and the onset potential is negatively shifted from 0.53 V to 0.23 V versus RHE. Combined photoluminescence, Mott-Schottky, open circuit potential, as well as electrochemical impedance spectroscopy analyses reveal the synergistic effect of hydrogenation treatment and Co-Pi deposition on enhancing the PEC performance of nanoporous BiVO 4 photoanode, facilitating both charge transportation and interfacial charge transfer without aggravating charge recombination.