Systematic Constructing FeOCl/BiVO4 Hetero‐Interfacial Hybrid Photoanodes for Efficient Photoelectrochemical Water Splitting

Abstract Bismuth vanadate (BiVO 4 ), as a promising photoanode for photoelectrochemical (PEC) water splitting, suffers from poor charge separation efficiency and light absorption efficiency. Herein, iron oxychloride (FeOCl) is introduced as a novel cocatalyst simply grafted on BiVO 4 to construct an integrated photoanode, enhancing PEC performance. The optimized FeOCl/BiVO 4 photoanode exhibits a superior photocurrent density value of 5.23 mA cm −2 at 1.23 V versus reversible hydrogen electrode (RHE) under AM 1.5G illuminations. From experimental analysis, such high PEC performance is ascribed to the unique properties of FeOCl, facilitating charge transport, increasing light absorption efficiency, and promoting water oxidation kinetics. Density functional theory calculations further confirm that FeOCl optimizes the Gibbs free energy of H and O‐containing intermediates (OOH * ) during PEC processes, boosting the catalytic kinetics of PEC water splitting. This work presents FeOCl as a promising catalyst for constructing high efficient PEC water‐splitting photoanodes.