Epitaxial growth of Ni(OH)2 nanoclusters on MoS2 nanosheets for enhanced alkaline hydrogen evolution reaction.
Epitaxial growth of Ni(OH)2 nanoclusters on MoS2 nanosheets for enhanced alkaline hydrogen evolution reaction.
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DOI：
10.1039/c8nr07045h
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发表时间：
2018-10
期刊：
影响因子：
6.7
通讯作者：
Guoqiang Zhao;Yue Lin;Kun Rui;Qian Zhou;Yaping Chen;S. Dou;Wenping Sun
中科院分区：
文献类型：
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作者：
Guoqiang Zhao;Yue Lin;Kun Rui;Qian Zhou;Yaping Chen;S. Dou;Wenping Sun
构建异质结构是设计高效电催化剂的有效策略。MoS_2是酸性介质中析氢反应(HER)的明星催化剂，但由于水分解过程缓慢，碱性HER活性不足。本文在碱性条件下合成了在MoS_2表面外延修饰了Ni(OH)_2纳米团簇的Ni(OH)_2/MoS_2异质结构。与MoS_2相比，外延Ni(OH)_2/MoS_2异质结在1M KOH中的活性显著增强，过电位降低了近150 mV，电流密度达到10 mA·cm~(-2)。翻转频率(TOF)的大幅提高表明，Ni(OH)2纳米团簇的引入大大提高了催化剂的本征活性。当MoS2准备好吸附和结合生成的H*时，Ni(OH)2纳米团簇的存在将提供更多的水解离位，这种所谓的协同效应最终导致显著增强的碱性HER动力学。此外，Ni(OH)2向MoS_2的电子转移增加了MoS_2的质子亲和力。目前的结果描述了一个有趣的案例，一种原子尺度的电化学惰性材料促进了她的过程，并将为设计面向电催化应用的高效异质纳米结构开辟一条新的途径。
Constructing heterostructures is an effective strategy for designing efficient electrocatalysts. MoS2 is a star catalyst for hydrogen evolution reaction (HER) in acidic media; however, the alkaline HER activity is deficient due to the sluggish water dissociation process. Herein, Ni(OH)2/MoS2 heterostructures with Ni(OH)2 nanoclusters epitaxially decorated on the surface of MoS2 are synthesized towards the alkaline HER. As compared with MoS2, the epitaxial Ni(OH)2/MoS2 heterostructures show significantly enhanced HER activity in 1 M KOH, and the overpotential is decreased by nearly 150 mV to reach a current density of 10 mA cm-2. The substantial increase in turnover frequency (TOF) demonstrates that the intrinsic activity is greatly improved after the incorporation of Ni(OH)2 nanoclusters. The presence of Ni(OH)2 nanoclusters would provide additional water dissociation sites while MoS2 is ready for the adsorption and combination of the generated H*, and this so-called synergistic effect eventually induces significantly enhanced alkaline HER kinetics. Besides, the electron transfer from Ni(OH)2 to MoS2 increases the proton affinity of MoS2. The present results describe an interesting case of an atomic-scale electrochemically inert material promoted HER process, and would open a new avenue into designing efficient hetero-nanostructures towards electrocatalytic applications.