Quan Li, Jiang Hui, Mei Guoliang, Sun Yujie, You Bo
Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States.
Chem Rev. 2024 Apr 10;124(7):3694-3812. doi: 10.1021/acs.chemrev.3c00332. Epub 2024 Mar 22.
Electrocatalytic water splitting driven by renewable electricity has been recognized as a promising approach for green hydrogen production. Different from conventional strategies in developing electrocatalysts for the two half-reactions of water splitting (e.g., the hydrogen and oxygen evolution reactions, HER and OER) separately, there has been a growing interest in designing and developing bifunctional electrocatalysts, which are able to catalyze both the HER and OER. In addition, considering the high overpotentials required for OER while limited value of the produced oxygen, there is another rapidly growing interest in exploring alternative oxidation reactions to replace OER for hybrid water splitting toward energy-efficient hydrogen generation. This Review begins with an introduction on the fundamental aspects of water splitting, followed by a thorough discussion on various physicochemical characterization techniques that are frequently employed in probing the active sites, with an emphasis on the reconstruction of bifunctional electrocatalysts during redox electrolysis. The design, synthesis, and performance of diverse bifunctional electrocatalysts based on noble metals, nonprecious metals, and metal-free nanocarbons, for overall water splitting in acidic and alkaline electrolytes, are thoroughly summarized and compared. Next, their application toward hybrid water splitting is also presented, wherein the alternative anodic reactions include sacrificing agents oxidation, pollutants oxidative degradation, and organics oxidative upgrading. Finally, a concise statement on the current challenges and future opportunities of bifunctional electrocatalysts for both overall and hybrid water splitting is presented in the hope of guiding future endeavors in the quest for energy-efficient and sustainable green hydrogen production.
由可再生电力驱动的电催化水分解已被认为是一种有前景的绿色制氢方法。与分别开发用于水分解两个半反应（例如析氢反应和析氧反应，HER和OER）的电催化剂的传统策略不同，设计和开发能够同时催化HER和OER的双功能电催化剂的兴趣日益浓厚。此外，考虑到OER所需的高过电位以及所产生氧气的价值有限，人们对探索替代氧化反应以取代OER用于混合水分解以实现高效节能制氢的兴趣也在迅速增长。本综述首先介绍水分解的基本方面，然后深入讨论常用于探测活性位点的各种物理化学表征技术，重点是双功能电催化剂在氧化还原电解过程中的重构。全面总结并比较了基于贵金属、非贵金属和无金属纳米碳的各种双功能电催化剂在酸性和碱性电解质中用于全水分解的设计、合成及性能。接下来，还介绍了它们在混合水分解中的应用，其中替代阳极反应包括牺牲剂氧化、污染物氧化降解和有机物氧化升级。最后，对双功能电催化剂在全水分解和混合水分解方面当前面临的挑战和未来机遇进行了简要阐述，希望能为未来寻求高效节能和可持续绿色制氢的努力提供指导。
