Electrochemical seawater splitting is a promising technique because it addresses two major challenges, clean energy production and seawater desalination, at the same time. Therefore, seeking out a facile and cost-effective way to synthesize highly active and stable seawater-splitting catalysts is of great interest to both the research community and industry. Here we developed an Fe²⁺-driven, one-step, and spontaneous fabrication method for a seawater-oxygen-evolution-active NiFe layered double hydroxide (LDH) at room temperature. The NiFe LDH was found to exhibit very high activity and stability toward the oxygen evolution reaction (OER) in an alkaline natural seawater electrolyte, delivering current densities of 100 and 500 mA/cm² at low overpotentials of 247 and 296 mV, respectively, and with no significant degradation observed over long-term stability testing of 96 h under a large current density of 500 mA/cm² in 1 M KOH seawater electrolyte. After coupling with a good hydrogen evolution reaction (HER) catalyst, NiMoN, the two-electrode electrolyzer was found to achieve current densities of 10, 100, and 500 mA/cm² at voltages of 1.477, 1.533, and 1.665 V, respectively, in alkaline natural seawater with good durability over 100 h at 500 mA/cm². The oxidation of Fe²⁺ is the driving force for the growth of NiFe LDH, and this mechanism is universal to the fabrication of other Fe-based hydroxides as efficient OER catalysts.

电化学海水分离是一项很有前途的技术，因为它同时解决了两个主要挑战，即清洁能源生产和海水淡化。因此，寻找一种简便且具有成本效益的方法来合成高活性和稳定的海水分解催化剂对研究界和工业界都具有极大的兴趣。在这里，我们开发了一种Fe ²⁺驱动的，一步一步的，室温下自发制造海水-氧-放出活性的NiFe层状双氢氧化物（LDH）的方法。发现NiFe LDH在碱性天然海水电解质中对氧释放反应（OER）表现出非常高的活性和稳定性，可提供100和500 mA / cm ^2的电流密度在1 M KOH海水电解质中以500 mA / cm ²的大电流密度在96 h的长期稳定性测试下，分别在247和296 mV的低超电势下没有观察到明显的降解。在与良好的析氢反应（HER）催化剂NiMoN偶联后，发现两电极电解槽在1.477、1.533和1.665 V的电压下分别达到10、100和500 mA / cm ^2的电流密度，在碱性天然海水中，在500 mA / cm ^{2的条件下，}在100小时内具有良好的耐久性。Fe ²⁺的氧化是NiFe LDH生长的驱动力，这种机制对于制造其他Fe基氢氧化物作为有效的OER催化剂是普遍的。