Sustainable hydrogen production by electrocatalytic water splitting is a promising energy storage technology yet challenging due to the sluggish kinetics of the oxygen evolution reaction (OER). Rationally designed robust and high-efficiency non-noble metal electrocatalysts for large-current-density OER are highly desirable for industrial-grade hydrogen production. Herein, a unique hierarchical heterostructure electrocatalyst composed of FeCo layered double hydroxide nanosheets and a NiSe nanowire array grown on Ni foam (FeCo LDH/NiSe@NF) is demonstrated. The optimized FeCo LDH/NiSe@NF exhibits an excellent OER activity with low overpotentials of 230, 266 and 298 mV at current densities of 100, 500 and 1000 mA cm⁻² in an alkaline solution. In particular, it can deliver 1000 mA cm⁻² without much decay after the long-term stability test for 100 h. Both the experimental results and theoretical calculations reveal that reasonable construction of a hierarchical heterostructure, as well as the strong interaction at the heterointerface between NiSe and FeCo LDH can not only offer sufficient exposure of the surface active sites, better electrochemical conductivity and structural stability, but also effectively optimize electronic configurations and lower the reaction energy barriers, consequently facilitating the reaction kinetics especially in large-current-density alkaline water electrolysis. Moreover, a two-electrode electrolyzer using FeCo LDH/NiSe@NF and NiCoP/NiCoS_x@NF as the anode and cathode only needs a cell voltage of 1.849 V to reach 1000 mA cm⁻² in 30 wt% KOH solution at 80 °C. The high catalytic activity and long-term stability of the catalyst at large current densities have exceeded most electrocatalysts reported, highlighting its great potential in large-scale applications.

中文翻译：

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多级 FeCo LDH/NiSe 异质结构电催化剂，具有丰富的异质界面，可在工业级电流密度下实现稳健的水分解


通过电催化分解水可持续制氢是一种很有前途的储能技术，但由于析氧反应 （OER） 的动力学缓慢，因此具有挑战性。用于大电流密度 OER 的合理设计坚固且高效的非贵金属电催化剂非常适合工业级氢气生产。在此，展示了一种独特的多级异质结构电催化剂，该电催化剂由 FeCo 层状双氢氧化物纳米片和在泡沫镍上生长的 NiSe 纳米线阵列 （FeCo LDH/NiSe@NF） 组成。优化的 FeCo LDH/NiSe@NF 在碱性溶液中，在 100、500 和 1000 mA ^cm-2 的电流密度下表现出优异的 OER 活性，具有 230、266 和 298 mV 的低过电位。特别是，它可以在 100 小时的长期稳定性测试后提供 1000 mA ^cm-2 而不会产生太大的衰减。实验结果和理论计算都表明，合理构建多级异质结构，以及 NiSe 和 FeCo LDH 在异质界面处的强相互作用，不仅可以提供足够的表面活性位点曝光、更好的电化学导电性和结构稳定性，还可以有效优化电子构型，降低反应能垒。 因此促进了反应动力学，尤其是在大电流密度碱性水电解中。此外，使用 FeCo LDH/NiSe@NF 和 NiCoP/NiCoS_x@NF 作为阳极和阴极的双电极电解槽只需要 1.849 V 的电池电压，即可在 80 °C 下在 30 wt% KOH 溶液中达到 1000 mA ^cm-2。 催化剂在大电流密度下的高催化活性和长期稳定性已经超过了大多数报道的电催化剂，凸显了其在大规模应用中的巨大潜力。