Developing innovative water electrolysis system to realize the energy-saving hydrogen production and prevent the H/O mixing is of vital importance for further boosting the sustainable development of water electrolysis for hydrogen production. Recent years have witnessed the rapid expansion of the research about the coupled and decoupled water electrolysis, in which the coupled water electrolysis system is associated with the replacement of anodic oxygen evolution reaction (OER) with kinetically favorable sacrificial agent or biomass oxidation reaction, and the decoupled water electrolysis can be described as separating hydrogen evolution reaction (HER) and OER by introducing appropriate redox mediators. To gain a deep understanding of these two interesting research fields, we here organize a comprehensive review of the recent progress of coupled and decoupled electrochemical water splitting for boosting hydrogen production. After providing a discussion about the fundamentals of decoupled and coupled water splitting and comparing with conventional water electrolysis, we have highlighted the advantages of these two systems. Subsequently, a comprehensive discussion about the application of these two systems are provided, including the structural features, reaction mechanisms, and the properties of decoupled systems. Finally, the challenges and perspectives of these two water electrolysis systems for the commercialization are manifested.

中文翻译：

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用于促进氢析出的耦合和解耦合电化学水分解：回顾和展望

开发创新的水电解系统，实现节能制氢、防止H/O混合，对于进一步推动水电解制氢的可持续发展具有重要意义。近年来，耦合和解耦合水电解的研究迅速扩展，其中耦合水电解系统是用动力学上有利的牺牲剂或生物质氧化反应取代阳极析氧反应（OER），并且与阳极析氧反应（OER）相关。解耦水电解可以描述为通过引入适当的氧化还原介体来分离析氢反应（HER）和OER。为了深入了解这两个有趣的研究领域，我们在这里对耦合和解耦合电化学水分解促进氢气生产的最新进展进行了全面的回顾。在讨论了解耦和耦合水分解的基本原理并与传统水电解进行比较后，我们强调了这两种系统的优点。随后，对这两个系统的应用进行了全面的讨论，包括结构特征、反应机制和解耦系统的性质。最后，阐述了这两种水电解系统商业化的挑战和前景。