Electrocatalytic hydrogen evolution reaction (HER) in alkaline solution is hindered by its sluggish kinetics toward water dissociation. Nickel-based catalysts, as low-cost and effective candidates, show great potentials to replace platinum (Pt)-based materials in the alkaline media. The main challenge regarding this type of catalysts is their relatively poor durability. In this work, we conceive and construct a charge-polarized carbon layer derived from carbon quantum dots (CQDs) on Ni₃N nanostructure (Ni₃[email protected]) surfaces, which simultaneously exhibit durable and enhanced catalytic activity. The Ni₃[email protected] shows an overpotential of 69 mV at a current density of 10 mA cm^–2 in a 1 M KOH aqueous solution, lower than that of Pt electrode (116 mV) at the same conditions. Density functional theory (DFT) simulations reveal that Ni₃N and interfacial oxygen polarize charge distributions between originally equal C–C bonds in CQDs. The partially negatively charged C sites become effective catalytic centers for the key water dissociation step via the formation of new C–H bond (Volmer step) and thus boost the HER activity. Furthermore, the coated carbon is also found to protect interior Ni₃N from oxidization/hydroxylation and therefore guarantees its durability. This work provides a practical design of robust and durable HER electrocatalysts based on nonprecious metals.

中文翻译：

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极化，碳-镍催化表面的结构，可进行强力，持久和经济的氢生成反应

碱溶液中的电催化氢放出反应（HER）受其对水离解的缓慢动力学的阻碍。镍基催化剂作为低成本和有效的候选物，显示出在碱性介质中替代基于铂（Pt）的材料的巨大潜力。关于这类催化剂的主要挑战是它们相对较差的耐久性。在这项工作中，我们构思并构建了一个在Ni ₃ N纳米结构（Ni ₃ [受电子邮件保护]）表面上衍生自碳量子点（CQDs）的电荷极化碳层，该碳层同时展现出持久且增强的催化活性。Ni ₃ [受电子邮件保护]在电流密度为10 mA cm ^–2时显示69 mV的过电势在相同条件下，在1 M KOH水溶液中的溶液低于Pt电极的溶液（116 mV）。密度泛函理论（DFT）模拟表明，Ni ₃ N和界面氧使CQD中原本相等的C–C键之间的电荷分布极化。通过形成新的C–H键（沃尔默步骤），部分带负电荷的C位点成为关键的水离解步骤的有效催化中心，从而提高了HER活性。此外，还发现涂覆的碳可保护内部Ni ₃ N免受氧化/羟基化，因此可确保其耐用性。这项工作提供了基于非贵金属的坚固耐用的HER电催化剂的实用设计。