Developing low-cost and high-effective bifunctional electrocatalysts is an efficient way to reduce the energy consumption of hydrogen production via electrochemical water splitting. Herein, 3D heterogeneous core-shell Co(OH)₂/NiS nanoarrays supported on nickel foam (Co(OH)₂/NiS/NF) were prepared by an easy stepwise hydrothermal strategy and the next electrochemical deposition process. The as-prepared Co(OH)₂/NiS/NF composite was used as an effective electrocatalyst for overall water splitting. A series of electrocatalyst with different shell thickness were gained by controlling the time of the electrochemical deposition. The optimized Co(OH)₂/NiS/NF-400 s electrocatalyst presented good catalytic activity for the HER in 1.0 M KOH, the overpotentials is 69 mV at a current density of 10 mA cm⁻² and the Tafel slope is 125 mV dec⁻¹. Furthermore, the alkaline electrolyzer used Co(OH)₂/NiS/NF-400 s as both the cathode and anode catalyst acquired low cell voltage of 1.53 V at 10 mA cm⁻² and showed excellent electrochemistry stability. The results illustrated that the as-prepared heterogeneous core-shell electrocatalyst can be used as an efficient catalyst for overall water splitting.

开发低成本，高效的双功能电催化剂是减少通过电化学水分解制氢的能源消耗的有效方法。在此，通过简单的逐步水热策略和接下来的电化学沉积工艺制备了支撑在泡沫镍上的3D异质核壳Co（OH）₂ / NiS纳米阵列（Co（OH）₂ / NiS / NF）。所制备的Co（OH）₂ / NiS / NF复合材料用作总水分解的有效电催化剂。通过控制电化学沉积的时间，获得了一系列具有不同壳厚度的电催化剂。优化的Co（OH）₂/ NiS / NF-400 s电催化剂在1.0 M KOH中对HER表现出良好的催化活性，在10 mA cm ^-2的电流密度下，过电势为69 mV，Tafel斜率为125 mV dec ^-1。此外，碱性电解槽使用Co（OH）₂ / NiS / NF-400 s作为阴极和阳极催化剂两者，在10mA cm ^-2下获得1.53V的低电池电压，并显示出优异的电化学稳定性。结果表明，所制备的非均相核-壳电催化剂可以用作有效的整体水分解催化剂。