Zheng Xingqun, Peng Lishan, Li Li, Yang Na, Yang Yanjun, Li Jing, Wang Jianchuan, Wei Zidong
The State Key Laboratory of Power Transmission Equipment & System Security and New Technology , Chongqing Key Laboratory of Chemical Process for Clean Energy and Resource Utilization , School of Chemistry and Chemical Engineering , Chongqing University , Shazhengjie 174 , Chongqing 400044 , P. R. China . Email:
Key Laboratory of Fuel Cell Technology of Hubei Province , Wuhan University of Technology , Wuhan 430070 , P. R. China.
Chem Sci. 2018 Jan 4;9(7):1822-1830. doi: 10.1039/c7sc04851c. eCollection 2018 Feb 21.
The transition-metal compounds (MX) have gained wide attention as hydrogen evolution reaction (HER) electrocatalysts; however, the interaction between the non-metallic atom (X) and the metal atom (M) in MX, and the role of X in the enhanced catalytic activity of MX, are still ambiguous. In this work, we constructed a simple model [X/Ni(100)] to decipher the contribution of X towards enhancing the catalytic activity of NiX, which allows us to accurately predict the trend in HER catalytic activity of NiX based on the easily accessible physico-chemical characteristics of X. Theoretical calculations showed that the electronegativity () and the principle quantum number () of X are two important descriptors for evaluating and predicting the HER catalytic activity of NiX catalysts effectively. X atoms in the VIA group can enhance the HER activity of X/Ni(100) more significantly than those in the second period due to the large χ or . At a relatively low X coverage, the S/Ni(100) possesses the best HER activity among all of the discussed X/Ni(100) models, and the optimum surface S : Ni atomic ratio is about 22-33%. Further experiments demonstrated that the Ni-NiS catalyst with a surface S : Ni atomic ratio of 28.9% exhibits the best catalytic activity and lowest charge transfer resistance. The trend in catalytic activity of NiX with differing X offers a new possible strategy to exploit MX materials and design new active catalysts rationally.
过渡金属化合物（MX）作为析氢反应（HER）电催化剂已受到广泛关注；然而，MX中非金属原子（X）与金属原子（M）之间的相互作用，以及X在增强MX催化活性中的作用仍不明确。在这项工作中，我们构建了一个简单模型[X/Ni(100)]来解读X对增强NiX催化活性的贡献，这使我们能够基于X易于获取的物理化学特性准确预测NiX的HER催化活性趋势。理论计算表明，X的电负性（χ）和主量子数（n）是有效评估和预测NiX催化剂HER催化活性的两个重要描述符。由于较大的χ或n，第VIA族中的X原子比第二周期中的X原子更能显著增强X/Ni(100)的HER活性。在相对较低的X覆盖度下，S/Ni(100)在所有讨论的X/Ni(100)模型中具有最佳的HER活性，最佳表面S:Ni原子比约为22 - 33%。进一步的实验表明，表面S:Ni原子比为28.9%的Ni-NiS催化剂表现出最佳的催化活性和最低的电荷转移电阻。不同X的NiX催化活性趋势为开发MX材料和合理设计新型活性催化剂提供了一种新的可能策略。
