Ni nanoparticles (NPs) consisting of Ni, NiO, and Ni(OH)₂ were formed on Ti substrates by electrodeposition as electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. Additionally, the deposition parameters including the potential range and the scan rate were varied, and the resulting NPs were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy. The chemical composition of the NPs changed upon using different conditions, and it was found that the catalytic activity increased with an increase in the amount of NiO. From these data, optimized NPs were synthesized; the best sample showed an onset potential of approximately 0 V and an overpotential of 197 mV at a cathodic current density of 10 mA cm⁻² as well as a small Tafel slope of 88 mV dec⁻¹ in 1 m KOH, values that are comparable to those of Pt foil. These NPs consist of approximately 25 % Ni and Ni(OH)₂ each, as well as approximately 50 % NiO. This implies that to obtain a successful HER electrocatalyst, active sites with differing compositions have to be close to each other to promote the different reaction steps. Long‐time measurements (30 h) showed almost complete transformation of the highly active catalyst compound consisting of Ni⁰, NiO, and Ni(OH)₂ into the less active Ni(OH)₂ phase. Nevertheless, the here‐employed electrodeposition of nonprecious metal/metal‐oxide combination compounds represents a promising alternative to Pt‐based electrocatalysts for water reduction to hydrogen.

中文翻译：

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碱性氢放出反应的镍纳米粒子的电沉积：相关的电催化行为和化学组成。

由Ni，NiO和Ni（OH）₂组成的Ni纳米颗粒（NPs）通过电沉积在碱性溶液中作为电催化剂用于氢析出反应（HER）在Ti基板上形成。此外，包括电位范围和扫描速率在内的沉积参数也有所变化，并且通过扫描电子显微镜和X射线光电子能谱研究了所得的NP。NP的化学组成在不同条件下发生变化，并且发现催化活性随着NiO量的增加而增加。根据这些数据，合成了优化的NP。最佳样品在10 mA cm ^-2的阴极电流密度下显示约0 V的起始电势和197 mV的过电势以及在1  m KOH中的88 mV dec ^-1的小Tafel斜率，该值与Pt箔相当。这些NP分别由大约25％的Ni和Ni（OH）₂以及大约50％的NiO组成。这意味着为了获得成功的HER电催化剂，具有不同组成的活性位点必须彼此靠近以促进不同的反应步骤。长期测量（30小时）显示，由Ni ⁰，NiO和Ni（OH）₂组成的高活性催化剂化合物几乎完全转变为活性较低的Ni（OH）₂阶段。尽管如此，此处采用的非贵金属/金属氧化物组合化合物的电沉积方法是将水还原为氢的基于Pt的电催化剂的有前途的替代方法。