Exploiting economical and high‐performance bifunctional electrocatalysts toward hydrogen and oxygen evolution reactions (HER/OER) is at the heart of overall water splitting in large‐scale application. Herein, an in situ and stepwise strategy for synthesizing core–shell Ni₃(S_1−xSe_x)₂@NiOOH (0 ≤ x ≤ 1) nanoarray heterostructures on nickel foam with tailored compositions for enhancing water‐splitting performance is reported. A series of Ni₃(S_1−xSe_x)₂ nanostructures is firstly grown on nickel foam via an in situ reaction in a heated polyol solution system. Ni₃(S_1−xSe_x)₂@NiOOH nanocomposites are subsequently prepared via electrochemical oxidation and the oxidation degree is systematically investigated by varying the oxidation time. Benefitting from the vertical standing architecture, abundant exposed active sites, and synergetically interfacial enhancement, Ni₃(S_0.25Se_0.75)₂@NiOOH heterojunctions with electrochemical polarization for 8 h exhibit superior HER and OER behaviors, achieving a water‐splitting current density of 10 mA cm⁻² at a small overpotential of 320 mV as well as boosted reaction kinetics and long‐term stability. This work should shed light on the controllable synthesis of metal‐based hybrid materials and provide a promising direction for developing the highest‐performing electrocatalysts based on interfacial and heterostructural regulation for advanced electrochemical energy conversion technologies.

中文翻译：

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调整成分的镍泡沫原位制备异质结构以提高水分解性能

将经济，高性能的双功能电催化剂用于氢和氧的释放反应（HER / OER），是大规模应用中总水分解的核心。这里，原位和用于合成的芯-壳的Ni逐步策略₃（S _{1- X}硒_X）₂ @NiOOH（0≤ X ≤1）纳米阵列异质上泡沫镍与用于增强的水分解性能定制的组合物报道。首先在加热的多元醇溶液系统中通过原位反应在镍泡沫上生长一系列Ni ₃（S _{1- x} Se _x）₂纳米结构。镍₃随后通过电化学氧化制备（S _{1- x} Se _x）₂ @NiOOH纳米复合材料，并通过改变氧化时间来系统地研究氧化程度。Ni ₃（S _0.25 Se _0.75）₂ @NiOOH异质结具有电化学极化作用，持续8小时，具有垂直极化结构，丰富的暴露活性位点和协同界面增强的特性，具有优异的HER和OER行为，实现了水分解电流密度为10 mA厘米^-2在320 mV的小超电势下，提高了反应动力学和长期稳定性。这项工作应阐明金属杂化材料的可控合成，并为基于先进的电化学能量转换技术的界面和异质结构调控开发性能最高的电催化剂提供有希望的方向。