Photoelectrochemical (PEC) two-electron water-oxidation reaction is a promising route for renewable and on-site generation of HO as an alternative to the traditional anthraquinone process. However, large overpotential, low product selectivity, and poor stability limit its practical applications of PEC producing HO. This review discusses the fundamental aspects of two-electron water oxidation toward HO in a simple PEC device. It also presents the research background and all prevailing and recent breakthrough in the mechanisms of anodic HO generation. Afterward, it comprehensively reviews the progress made so far in enhancing the Faradaic efficiency of HO synthesis by tuning the thermodynamic energy barriers and reaction kinetics, facilitating the mass transfer of reactants and products, and stabilizing the products and catalytic surfaces. Finally, the critical challenges and opportunities for future development in this field are discussed. We believe that this review would stimulate further efforts to achieve highly efficient on-site HO production and high-power-density fuel cells with HO chemical utilization.

中文翻译：

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光电化学水氧化现场生产过氧化氢

光电化学（PEC）双电子水氧化反应是一种可再生和现场生成 H2O 的有前途的途径，可以替代传统的蒽醌工艺。然而，过电势大、产物选择性低、稳定性差等限制了PEC生产H2O的实际应用。本综述讨论了简单 PEC 装置中双电子水氧化为 H2O 的基本方面。它还介绍了阳极 H2O 生成机制的研究背景以及所有流行的和最新的突破。随后，全面回顾了迄今为止在通过调节热力学能垒和反应动力学、促进反应物和产物的传质以及稳定产物和催化表面来提高H2O合成的法拉第效率方面所取得的进展。最后，讨论了该领域未来发展的关键挑战和机遇。我们相信，这次审查将激发进一步的努力，以实现高效的现场 H2O 生产和利用 H2O 化学利用的高功率密度燃料电池。