Triple Functions of Ni(OH)2 on the Surface of WN Nanowires Remarkably Promoting Electrocatalytic Activity in Full Water Splitting
Triple Functions of Ni(OH)2 on the Surface of WN Nanowires Remarkably Promoting Electrocatalytic Activity in Full Water Splitting
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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的电催化活性
DOI：
10.1021/acscatal.0c02891
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发表时间：
2020-11-20
期刊：
影响因子：
12.9
通讯作者：
Zhang, Chi
中科院分区：
文献类型：
--
作者：
Lv, Cuncai;Wang, Xiaobo;Zhang, Chi
寻找高效、有前景的非贵金属催化剂用于碱性析氢反应，对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，即在碳纤维纸(WN-Ni(OH)(2))上负载Ni(OH)(2)壳的WN纳米线核心涂层。在1M KOH溶液中，分级电催化剂在170 mV的过电位下提供20 mA cm(-2)的电流密度，在245 mV时提供100 mA cm(-2)的电流密度。WN-Ni(OH)(2)在HER中的增强作用归因于WN和Ni(OH)(2)之间的协同作用：在水解离过程中，羟基优先吸附在WN上，氢优先吸附在Ni(OH)(2)上，同时，Ni(OH)(2)可以促进羟基从WN上脱附。因此，可以提高全表面Volmer反应动力学。结果表明，WN-Ni(OH)(2)降低了HER的活化能，提高了本征活性。同时，在析氧反应的过电位为339 mV，完全裂水反应的过电位为510 mV时，杂化电池的电流密度可达100 mA cm(-2)。这种界面合作提供了一种有前景的双功能电催化剂，也为在碱性介质中制备高效的氮化物基电催化剂提供了一种有希望的策略。
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.