Photochemical metal organic deposition of FeO x catalyst on BiVO 4 for improving solar-driven water oxidation efficiency

Abstract

Abstract Scheelite-monoclinic BiVO4 serving as a photoanode for photoelectrochemical water oxidation is known for its fast electron–hole recombination and slow kinetics, thus limiting its efficiency. In this study, a highly active oxygen evolution reaction catalyst, FeOx, is successfully deposited on BiVO4 by a simple and low energy needed photochemical metal organic deposition (PMOD) process under ambient environment. During the PMOD process, metal organic precursor goes through ligand-to-metal charge transfer, triggers by UV irradiation, and then reacts with oxygen to form a thin amorphous FeOx catalyst layer. This FeOx coated BiVO4 photoanode boosts the hole injection efficiency to ∼100% which is almost triple comparing to the bare BiVO4. Furthermore, with FeOx layer, the onset potential shifts cathodically for about 0.4 V and the photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) reaches 1.1 mA/cm2 which is 2.5 times of a bare BiVO4 photoanode. The stability of the photoanode is also improved. The FeOx coated BiVO4 demonstrates a substantial enhancement of the incident photon to current efficiency (IPCE) and the absorbed photon to current efficiency (APCE) due to its ability in increasing the hole injection efficiency and oxygen evolution reaction (OER) kinetics.