Recently, extensive efforts have been focused on CuO materials as the non-noble metal electrocatalysts for the oxygen evolution reaction (OER). However, their catalytic efficiency is still far from meeting the need of practical large-scale water splitting because of poor electrical conductivity and limited exposed active sites. Herein, we report that amorphous NiFe layered double hydroxide film can be grown on CuO nanorod arrays supported on Cu foil (NiFe-LDH/CuO NRs/CF) to construct a core–shell heterostructure via a facile electrochemical deposition approach. The resulting core–shell heterostructure demonstrates excellent OER performance in 1 M KOH, only requiring a small overpotential of 290 mV to drive the current density of 50 mV cm^–2 with a low Tafel slope of 60 mV dec^–1, and maintaining a steady current density of 50 mA cm^–2 for at least 35 h with negligible decline in catalytic activity, which is the best OER performance among reported CuO electrocatalysts to date. Remarkably, this catalytic performance is also superior to that of the state-of-the-art IrO₂ catalyst. The prominent catalytic performance of NiFe-LDH/CuO NRs could be attributed to the synergistic effect between NiFe-LDH film and CuO NRs. As a result, our research indicates that the construction of amorphous heterostructures could be a promising strategy for development of efficient OER systems.

中文翻译：

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包覆无定形NiFe层状双氢氧化物膜的CuO纳米棒阵列增强电催化水氧化活性

近来，已经将广泛的努力集中在CuO材料上，作为用于氧析出反应（OER）的非贵金属电催化剂。但是，由于电导率差和暴露的活性位点有限，它们的催化效率仍远远不能满足实际大规模水分解的需要。在本文中，我们报道非晶NiFe层状双氢氧化物膜可以在铜箔（NiFe-LDH / CuO NRs / CF）上支撑的CuO纳米棒阵列上生长，以通过简便的电化学沉积方法构建核-壳异质结构。由此产生的核-壳异质结构在1 M KOH中表现出出色的OER性能，只需要290 mV的小过电位即可驱动50 mV cm ^–2的电流密度，而60伏特dec ^–1的低Tafel斜率，并在至少35 h内保持50 mA cm ^–2的稳定电流密度，且催化活性下降可忽略不计，这是迄今为止报道的CuO电催化剂中最佳的OER性能。显着地，该催化性能也优于现有技术的IrO ₂催化剂。NiFe-LDH / CuO NRs的突出催化性能可归因于NiFe-LDH膜与CuO NRs的协同作用。结果，我们的研究表明，非晶异质结构的构建可能是开发高效OER系统的有前途的策略。