Discovering efficient and promising non-noble catalysts toward the alkaline hydrogen evolution reaction (HER) is vital for a clean energy system. Here, we design an efficient alkaline HER electrocatalyst, coating of WN nanowire core with a Ni(OH)₂ shell supported on a carbon fiber paper (WN-Ni(OH)₂). In a 1 M KOH solution, the hierarchical electrocatalyst affords a current density of 20 mA cm^–2 at an overpotential of 170 mV and 100 mA cm^–2 at 245 mV. The enhanced performance of WN-Ni(OH)₂ in the HER is attributed to the synergy between WN and Ni(OH)₂: during water dissociation, hydroxyl groups are preferentially adsorbed on WN and hydrogen on Ni(OH)₂; meanwhile, Ni(OH)₂ could promote hydroxyl group desorption from WN. Thus, the full-surface Volmer reaction kinetics could be enhanced. As a consequence, the WN-Ni(OH)₂ has a reduced activation energy of the HER and enhanced intrinsic activity performance. Meanwhile, the hybrid can reach a current density of 100 mA cm^–2 at an overpotential of 339 mV for the oxygen evolution reaction (OER), and an overpotential of 510 mV for the full water-splitting reaction. This interfacial cooperation offers a promising bifunctional electrocatalyst, as well as a hopeful strategy for fabricating efficient nitride-based electrocatalysts in alkaline media.

中文翻译：

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WN纳米线表面Ni（OH）_2的三重功能显着促进全水分解中的电催化活性

对于碱性氢释放反应（HER），发现有效且有前途的非贵族催化剂对于清洁能源系统至关重要。在这里，我们设计了一种高效的碱性HER电催化剂，在WN纳米线芯上涂覆了一层Ni（OH）₂壳，并被碳纤维纸（WN-Ni（OH）₂）支撑。在1 M KOH溶液中，分层电催化剂在170 mV的过电势下提供20 mA cm ^–2的电流密度，在245 mV的情况下提供100 mA cm ^–2的电流。WN-Ni（OH）₂在HER中的增强性能归因于WN和Ni（OH）₂之间的协同作用：在水离解过程中，羟基优先吸附在WN上，氢优先吸附在Ni（OH）_2上; 同时，Ni（OH）₂可以促进WN脱附羟基。因此，可以提高全表面沃尔默反应动力学。结果，WN-Ni（OH）₂具有降低的HER活化能和增强的固有活性性能。同时，对于氧气析出反应（OER），在339 mV的超电势下，对于完全水分解反应，在510 mV的超电势下，混合电流可以达到100 mA cm ^–2的电流密度。这种界面合作提供了有希望的双功能电催化剂，以及在碱性介质中制备有效的基于氮化物的电催化剂的有希望的策略。