Houjiang Liu, Hongwei Cong, Guijun Yang Guijun Yang, Chuangchuag Gong, Jiawei Ding, Yuan yuan Fu, Jin Cui, Kai Song, Bingxu Chen, Chunnian He, Naiqin Zhao, Jinhua Ye, Fang He
Abstract The self-trapping of charge carriers, resulting in the formation of polarons, significantly restricts the separation and transport of charge carriers in photoelectrochemical systems. Herein, using bismuth vanadate as a model photoanode, we propose a surface-selective strategy to regulate hole polarons. Density functional theory calculations predict that substituting bismuth ions with indium ions suppresses hole polaron formation by weakening electron-phonon coupling. This substitution is achieved through a liquid-phase cation exchange method, enabling precise surface modification. The electron paramagnetic resonance, temperature-dependent photoluminescence spectroscopy, in situ irradiation X-ray photoelectron spectroscopy, and femtosecond time-resolved absorption spectroscopy all confirm the suppression of hole polaron formation. After loading co-catalyst, the optimized photoanode achieves a water-splitting photocurrent density of 6.46 mA cm -2 at 1.23 V versus the reversible hydrogen electrode, with an applied bias photo-to-current efficiency of 2.19%. The unbiased tandem system exhibits a solar-to-hydrogen conversion efficiency of 6%. Here, we show that suppressing surface hole polaron formation facilitates hole carrier release, offering a pathway for enhancing photoelectrochemical performance.