Highly Coupled Dynamically Modulated Electrocatalysts on Wafer‐Scale InGaN/GaN Nanowires on Silicon for Successive Acidic Photoelectrochemical Water Oxidation

Abstract Photoelectrochemical water splitting is considered one of the most promising paths for sustainable hydrogen production. However, the sluggish kinetics of the water oxidation reaction and poor stability of the photoanode significantly limit the overall performance of the photoelectrochemical device, particularly under acidic conditions, which poses great challenges for practical applications. Herein, the coupling of unique CoRuO x nanoclusters with dynamic electronic modulation effects to wafer‐scale InGaN nanowires is proposed, demonstrating superior photoelectrochemical activity and stability for acidic water oxidation. Compared with InGaN nanowires loaded with typical RuO₂ cocatalysts, CoRuO x /InGaN photoanodes achieve a remarkable improvement in applied bias photon‐to‐current efficiency from 0.77% to 2.25%, with stable operation for over 500 min under strongly acidic conditions. Such boosted performance is attributed mainly to Co induced dynamic electronic modulation, which enhances oxygen evolution while maintaining the stable operation of CoRuO x /InGaN photoanodes. Initially, the Co sites increased the oxidation state of Ru, enhancing the activity of oxygen evolution. Moreover, during PEC operation, the Co sites stabilized the Ru sites, preventing dissolution of cocatalyst. This unique self‐adaptive process significantly enhances the stability and activity of the photoanode, opening an effective avenue to achieve efficient and durable photoanodes for PEC applications.