Hydrogen can be sustainably produced through photoelectrochemical (PEC) water splitting. The process of PEC water splitting is composed of two vital half-reactions: water oxidation to O2 on photoanode, and proton reduction to H2 on photocathode. Both in thermodynamics and kinetics, the oxidation of water on photoanode is much more challenging, because the formation of O2 involves the four-holes reaction process that is more difficult than the two-protons reduction. Accordingly, the oxidation of water into O2 is the rate-determining reaction for PEC water splitting, which is closely affected by the light harvesting, charge separation and transfer, as well as surface activity of photoanode. In principle, water oxidation is initiated by the photo-excited charge of photoanode. In this review, we took hematite photoanode as a typical example to illustrate the progress in modifying the charge separation and migration property of metal-oxide photoanodes for water oxidation. The typical strategies adopted to facilitate the charge transfer and separation of hematite photoanode were specifically summarized. In addition, the views designing and developing hematite photoanode with high-performance for water oxidation were presented. This review provides comprehensive information about the state-of-the-art progress of hematite-based photoanodes and forecast the developing directions of photoanode materials for solar water splitting.

中文翻译：

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促进电荷转移以增强析氧反应的典型策略：赤铁矿案例研究

氢可以通过光电化学 (PEC) 水分解可持续生产。PEC 水分解过程由两个重要的半反应组成：光阳极上的水氧化成 O2，光电阴极上的质子还原成 H2。无论是在热力学还是动力学上，水在光阳极上的氧化都更具挑战性，因为 O2 的形成涉及比双质子还原更困难的四孔反应过程。因此，水氧化成 O2 是 PEC 水分解的速率决定反应，它与光捕获、电荷分离和转移以及光阳极的表面活性密切相关。原则上，水氧化是由光阳极的光激发电荷引发的。在这次审查中，我们以赤铁矿光阳极作为典型例子来说明在改变金属氧化物光阳极的电荷分离和迁移性能用于水氧化方面的进展。具体总结了用于促进赤铁矿光电阳极电荷转移和分离的典型策略。此外，还提出了设计和开发高性能水氧化赤铁矿光电阳极的意见。这篇综述提供了关于赤铁矿基光阳极最新进展的综合信息，并预测了用于太阳能分解水的光阳极材料的发展方向。具体总结了用于促进赤铁矿光电阳极电荷转移和分离的典型策略。此外，还提出了设计和开发高性能水氧化赤铁矿光电阳极的意见。这篇综述提供了关于赤铁矿基光阳极最新进展的综合信息，并预测了用于太阳能分解水的光阳极材料的发展方向。具体总结了用于促进赤铁矿光电阳极电荷转移和分离的典型策略。此外，还提出了设计和开发高性能水氧化赤铁矿光电阳极的意见。这篇综述提供了关于赤铁矿基光阳极最新进展的综合信息，并预测了用于太阳能分解水的光阳极材料的发展方向。