Exploring advanced electrocatalysts for overall seawater splitting is of great significance for large-scale green hydrogen production in which interface engineering has been considered as an effective strategy to enhance the intrinsic activities of the electrocatalysts. In this work, CeO_x-modified NiCo₂O₄ nanoneedle arrays are designed and constructed in situ grown on Ni foam (NF) through a facile two-step synthesis method. Density functional theory calculations reveal that the strong interaction between CeO_x and NiCo₂O₄ can regulate the electronic states of metal surfaces and optimize the electronic structures of the materials, essentially improving the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) properties. Specifically, in alkaline electrolytes, CeO_x@NiCo₂O₄/NF exhibits superior electrocatalytic activities and stabilities, requiring overpotentials of 238 mV for the OER and 144 mV for the HER to achieve a current density of 10 mA cm^–2. When applied to a simulated seawater splitting device, the CeO_x@NiCo₂O₄/NF also maintains a battery voltage of 1.66 V to reach 10 mA cm^–2 and exhibits good stability for over 60 h, with high faradic efficiencies (FEs) close to 100% for both the OER and HER.

中文翻译：

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自支撑 CeOx@NiCo2O4 阵列的界面工程整体海水分裂

探索用于整体海水分解的先进电催化剂对于大规模绿色制氢具有重要意义，其中界面工程被认为是增强电催化剂本征活性的有效策略。在这项工作中，通过简单的两步合成方法，设计并构建了在泡沫镍（NF）上原位生长的CeO _x修饰的NiCo ₂ O ₄纳米针阵列。密度泛函理论计算表明，CeO _x与NiCo ₂ O ₄之间的强相互作用可以调节金属表面的电子态，优化材料的电子结构，从本质上改善析氧反应（OER）和析氢反应（HER）特性。具体而言，在碱性电解质中，CeO _x @NiCo ₂ O _{4 /NF表现出优异的电催化活性和稳定性，OER需要238 mV的过电势，HER需要144 mV的过电势才能实现10 mA cm} ^–2的电流密度。当应用于模拟海水分裂装置时，CeO _x @NiCo ₂ O ₄ /NF也能保持1.66 V的电池电压达到10 mA cm ^–2，并在60小时以上表现出良好的稳定性，具有高法拉第效率（FE） OER 和 HER 都接近 100%。