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 BiVO4 photoanode. Linear sweep voltammograms show that after the combined treatment, photocurrent density of nanoporous BiVO4 photoanode is increased for ca. 3 times at 1.23V versus reversible hydrogen electrode (RHE), and the onset potential is negatively shifted from 0.53V to 0.23V 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 BiVO4 photoanode, facilitating both charge transportation and interfacial charge transfer without aggravating charge recombination.