The design of efficient, low-cost, and stable electrocatalyst systems toward energy conversion is highly demanding for their practical use. Large scale electrolytic water splitting is considered as a promising strategy for clean and sustainable energy production. Herein, we report a self-supported NiFe layered double hydroxide (LDH)-NiSe electrocatalyst by stepwise surface-redox-etching of Ni foam (NF) through a hydrothermal process. The as-prepared NiFe LDH-NiSe/NF catalyst exhibits far better performance in alkaline water oxidation, proton reduction, and overall water splitting compared to NiSe_x/NF or NiFe LDH/NF. Only 240 mV overpotential is required to obtain a water oxidation current density of 100 mA cm^–2, whereas the same for the hydrogen evolution reaction is 276 mV in 1.0 M KOH. The synergistic effect from NiSe and NiFe LDH leads to the evolution of a highly efficient catalyst system for water splitting by achieving 10 mA cm^–2 current density at only 1.53 V in a two-electrode alkaline electrolyzer. In addition, the designed electrode produces stable performance for a long time even at higher current density to demonstrate its robustness and prospective as a real-life energy conversion system.

中文翻译：

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自支撑镍铁层状双氢氧化物-硒化镍镍电催化剂具有优异的水分解活性

面向能量转换的高效，低成本和稳定的电催化剂系统的设计对其实际应用提出了很高的要求。大规模电解水分解被认为是清洁和可持续能源生产的有前途的策略。在这里，我们报告了通过水热工艺对镍泡沫（NF）进行逐步表面氧化还原蚀刻的自支撑NiFe层状双氢氧化物（LDH）-NiSe电催化剂。与NiSe _x / NF或NiFe LDH / NF相比，所制备的NiFe LDH-NiSe / NF催化剂在碱性水氧化，质子还原和总水分解方面表现出更好的性能。只需240 mV的超电势即可获得100 mA cm ^–2的水氧化电流密度，而在1.0 M KOH中，析氢反应的相同值为276 mV。NiSe和NiFe LDH的协同作用通过在两电极碱性电解槽中仅1.53 V时实现10 mA cm ^–2的电流密度，就导致了用于水分解的高效催化剂体系的发展。此外，设计的电极即使在较高的电流密度下也能长时间稳定运行，以证明其坚固性和作为现实生活中的能量转换系统的前景。