Liquid-Metal-Induced Hydrogen Insertion in Photoelectrodes for Enhanced Photoelectrochemical Water Oxidation.

Wang, Jinshu; Cheng, Houyan; Cui, Yuntao; Yang, Yunfei; He, Heng; Cai, Yongfeng; Wang, Zhiliang; Wang, Lianzhou et al. · ACS Nano · 2022

basic_science · Level V

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Abstract

Fast charge separation and transfer (CST) is essential for achieving efficient solar conversion processes. This CST process requires not only a strong driving force but also a sufficient charge carrier concentration, which is not easily achievable with traditional methods. Herein, we report a rapid hydrogenation method enabled by gallium-based liquid metals (GBLMs) to modify the prototypical WO<sub>3</sub> photoelectrode to enhance the CST for a PEC process. Protons in solution are controllably embedded into the WO<sub>3</sub> photoanode accompanied by electron injection due to the strong reduction capability of GBLMs. This process dramatically increases the carrier concentration of the WO<sub>3</sub> photoanode, leading to improved charge separation and transfer. The hydrogenated WO<sub>3</sub> photoanode exhibits over a 229% improvement in photocurrent density with long-term stability. The effectiveness of GBLMs treatment in accelerating the CST process is further proved using other more general semiconductor photoelectrodes, including Nb<sub>2</sub>O<sub>5</sub> and TiO<sub>2</sub>.