Carbon doping switching on the hydrogen adsorption activity of NiO for hydrogen evolution reaction
Carbon doping switching on the hydrogen adsorption activity of NiO for hydrogen evolution reaction
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碳掺杂对 NiO 析氢反应氢吸附活性的影响
DOI：
10.1038/s41467-020-14462-2
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发表时间：
2020-01-30
影响因子：
16.6
通讯作者：
Li, Yat
中科院分区：
文献类型：
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作者：
Kou, Tianyi;Chen, Mingpeng;Li, Yat
由于水的解离需要额外的能量，析氢反应（HER）在碱性介质中比在酸性介质中更缓慢。许多催化剂，包括NiO，提供水解离的活性位点已被广泛研究。然而，NiO的整体HER性能仍然受到缺乏有利的H吸附位点的限制。在这里，我们展示了一种通过碳掺杂来激活NiO的策略，这会产生有利于H吸附的配位不足的Ni位点。DFT计算表明，碳掺杂使Heyrovsky阶跃的能垒从1.17 eV降低到0.81 eV，表明碳也是水-碱HER中水分子解离的热点。结果表明，碳掺杂NiO催化剂在10 mA cm-2时获得了27 mV的超低过电位和36 mV dec-1的低Tafel斜率，代表了现有技术NiO催化剂中的最佳性能。
Hydrogen evolution reaction (HER) is more sluggish in alkaline than in acidic media because of the additional energy required for water dissociation. Numerous catalysts, including NiO, that offer active sites for water dissociation have been extensively investigated. Yet, the overall HER performance of NiO is still limited by lacking favorable H adsorption sites. Here we show a strategy to activate NiO through carbon doping, which creates under-coordinated Ni sites favorable for H adsorption. DFT calculations reveal that carbon dopant decreases the energy barrier of Heyrovsky step from 1.17 eV to 0.81 eV, suggesting the carbon also serves as a hot-spot for the dissociation of water molecules in water-alkali HER. As a result, the carbon doped NiO catalyst achieves an ultralow overpotential of 27 mV at 10 mA cm−2, and a low Tafel slope of 36 mV dec−1, representing the best performance among the state-of-the-art NiO catalysts.