Theoretical and Experimental Insight into the Effect of Nitrogen Doping on Hydrogen Evolution Activity of Ni3S2 in Alkaline Medium
Theoretical and Experimental Insight into the Effect of Nitrogen Doping on Hydrogen Evolution Activity of Ni3S2 in Alkaline Medium
复制标题
DOI：
10.1002/aenm.201703538
复制
发表时间：
2018-07-05
影响因子：
27.8
通讯作者：
Li, Yat
中科院分区：
文献类型：
--
作者：
Kou, Tianyi;Smart, Tyler;Li, Yat
硫化镍（Ni3S2）由于其金属导电性和在碱性介质中优异的稳定性，是一种很有前途的析氢反应（HER）催化剂。然而，报道的Ni3S2的催化活性仍然相对较低。本文提出了一种通过氮掺杂提高Ni3S2的H吸附能力和HER性能的有效策略。n掺杂Ni3S2纳米片在10 mA cm（-2）下获得了相当低的过电位155 mV，在1.0 m KOH电解质中获得了0.42 mA cm（-2）的优良交换电流密度。在155 mV下获得的质量活性为16.9 mA mg(-1)，周转频率为2.4 s(-1)，显著高于其他ni3s2基HER催化剂的报道值，与碱性介质中最佳HER催化剂的性能相当。这些实验数据和理论分析表明，n掺杂Ni3S2具有优异的催化活性是由于富集了具有良好H吸附自由能的活性位点。在Ni3S2中的活性与表面S原子的配位数和邻近Ni原子的电荷耗尽高度相关。这些新发现为今后实验设计和合成最佳HER催化剂提供了重要的指导。
Nickel sulfide (Ni3S2) is a promising hydrogen evolution reaction (HER) catalyst by virtue of its metallic electrical conductivity and excellent stability in alkaline medium. However, the reported catalytic activities for Ni3S2 are still relatively low. Herein, an effective strategy to boost the H adsorption capability and HER performance of Ni3S2 through nitrogen (N) doping is demonstrated. N-doped Ni3S2 nanosheets achieve a fairly low overpotential of 155 mV at 10 mA cm(-2) and an excellent exchange current density of 0.42 mA cm(-2) in 1.0 m KOH electrolyte. The mass activity of 16.9 mA mg(-1) and turnover frequency of 2.4 s(-1) obtained at 155 mV are significantly higher than the values reported for other Ni3S2-based HER catalysts, and comparable to the performance of best HER catalysts in alkaline medium. These experimental data together with theoretical analysis suggest that the outstanding catalytic activity of N-doped Ni3S2 is due to the enriched active sites with favorable H adsorption free energy. The activity in the Ni3S2 is highly correlated with the coordination number of the surface S atoms and the charge depletion of neighbor Ni atoms. These new findings provide important guidance for future experimental design and synthesis of optimal HER catalysts.