Nonprecious NiMo composites are promising hydrogen evolution reaction electrocatalysts due to their Pt-like catalytic surfaces. However, because of hydroxide adsorption in alkaline media, the oxidative elution of Mo deteriorates structural and catalytic stability. Herein, a Cu and Co incorporated NiMo composite (NiMoCuCo) is prepared as an active and durable hydrogen evolution reaction (HER) electrocatalyst by direct electrochemical deposition. The low electronegativities of Cu and Co effectively reduce the charge valence state of the metals and the zeta potential of the electrocatalysts, ameliorating surface electronegativity. NiMoCuCo shows a low overpotential of 53 mV at a current density of 10 mA cm⁻² and a slight overpotential increase of 0.01 mV h⁻¹ (1.8%) after a long-term stability test for 100 h at a current density of 100 mA cm⁻², outperforming NiMo and NiMoCu. Ex situ analyses demonstrate that NiMoCuCo exhibits a reduced charge valence state of Mo without significant degradation after the long-term stability test. Furthermore, Co in NiMoCuCo acts as the OH adsorption site on behalf of Mo, owing to the reduced surface electronegativity of Mo and strong OH affinity. This results in a balance between water dissociation and HER kinetics of NiMo composites, leading to excellent HER activity and stability.

中文翻译：

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一种高活性和耐用的 NiMoCuCo 催化剂，具有适度的氢氧化物吸附能，可实现高效的析氢反应


非贵金属 NiMo 复合材料由于其类 Pt 催化表面而成为有前途的析氢反应电催化剂。然而，由于氢氧化物在碱性介质中的吸附，Mo 的氧化洗脱会破坏结构和催化稳定性。在此，通过直接电化学沉积制备了 Cu 和 Co 掺入的 NiMo 复合材料 （NiMoCuCo） 作为活性和持久的析氢反应 （HER） 电催化剂。Cu 和 Co 的低电负性有效地降低了金属的电荷价态和电催化剂的 zeta 电位，从而改善了表面电负性。NiMoCuCo 在 10 mA ^cm-2 的电流密度下显示出 53 mV 的低过电位，在 100 mA ^cm-2 的电流密度下进行 100 h 的长期稳定性测试后，过电位略微增加 0.01 mV ^h-1 （1.8%），优于 NiMo 和 NiMoCu。非原位分析表明，NiMoCuCo 表现出 Mo 的降低电荷价态，在长期稳定性测试后没有明显的降解。此外，由于 Mo 的表面电负性降低且 OH 亲和力强，NiMoCuCo 中的 Co 代表 Mo 充当 OH 吸附位点。这导致 NiMo 复合材料的水解离和 HER 动力学之间的平衡，从而获得出色的 HER 活性和稳定性。