Li Shihang, Liu Wei, Guo Xinlong, Ding Boyu, Cao Aiqing, Sha Qihao, Shen Zudong, Yang Yongqiang, Zhang Yu, Zhang Yixin, Wang Kairui, Xin Huijun, Kuang Yun, Zhou Daojin, Sun Xiaoming
State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, 610500, P. R. China.
Small. 2025 Jul;21(27):e2502994. doi: 10.1002/smll.202502994. Epub 2025 May 15.
Seawater electrolysis offers a sustainable route for hydrogen production. Operating at high current densities can improve the energy efficiency but requires anodes that can sustain high oxygen evolution reaction (OER) activity, selectivity, and stability against negative effects of Cl. Herein, NiFeZn layered double hydroxide (NiFeZn-LDH) demonstrates remarkable OER performance, requiring only 220 mV overpotential to achieve 10 mA cm, and maintaining 100% selective seawater oxidation to oxygen for 500 h at an unprecedented current density of 3 A cm, with minimal degradation. Through comprehensive characterizations, it is found that the dissolution of the amphoteric Zn-site and the following formation of Zn vacancies are key to the excellent OER activity. The free Zn in electrolyte converts to Zn(OH) and adsorbs onto the electrode, facilitating the OH nucleophilic attack by disrupting the hydrogen bond network at the electrochemical interface. Furthermore, the steric hindrance of Zn(OH) suppresses the Cl competing adsorption, ensuring 100% OER selectivity and long-term stability. As a result, an industrial-scale electrolyzer with NiFeZn-LDH as the anode operates stably for over 700 h in a saturated NaCl electrolyte, consuming only 4.26 Nm H. This work demonstrates the feasibility of developing energy-efficient, highly stable seawater electrolyzers that outperform conventional water electrolyzers.
海水电解为制氢提供了一条可持续的途径。在高电流密度下运行可以提高能源效率，但需要阳极能够维持高析氧反应（OER）活性、选择性以及对Cl负面影响的稳定性。在此，镍铁锌层状双氢氧化物（NiFeZn-LDH）展现出卓越的OER性能，仅需220 mV过电位即可实现10 mA cm，并且在前所未有的3 A cm电流密度下将海水氧化为氧气的选择性保持100%达500小时，降解极小。通过全面表征发现，两性Zn位点的溶解以及随后Zn空位的形成是优异OER活性的关键。电解质中的游离Zn转化为Zn(OH)并吸附到电极上，通过破坏电化学界面处的氢键网络促进OH亲核攻击。此外，Zn(OH)的空间位阻抑制了Cl的竞争吸附，确保了100%的OER选择性和长期稳定性。结果，以NiFeZn-LDH为阳极的工业规模电解槽在饱和NaCl电解质中稳定运行超过700小时，仅消耗4.26 Nm H。这项工作证明了开发比传统水电解槽性能更优的节能、高稳定性海水电解槽的可行性。
