Pourbaix图
催化作用
化学
吉布斯自由能
密度泛函理论
电化学
氮气
碳纤维
过渡金属
物理化学
氢
无机化学
计算化学
热力学
材料科学
有机化学
电极
物理
复合材料
复合数
作者
Yuefeng Zhang,Zixun Yu,Fangxin She,Wei Li,Zhiyuan Zeng,Hao Li
标识
DOI:10.1016/j.jcis.2023.03.033
摘要
Under electrocatalytic conditions, the state of a catalyst surface (e.g., adsorbate coverage) can be very different from a pristine form due to the existing conversion equilibrium between water and H- and O-containing adsorbates. Dismissing the analysis of the catalyst surface state under operating conditionsmay lead to misleading guidelines for experiments. Given that confirming the actual active site of the catalyst under operating conditions is indispensable to providing practical guidance for experiments, herein, we analyzed the relations between the Gibbs free energy and the potential of a new type of molecular metal-nitrogen-carbon (MNC) dual-atom catalysts (DACs) with a unique 5 N-coordination environment, by spin-polarized density functional theory (DFT) and surface Pourbaix diagram calculations. Analyzing the derived surface Pourbaix diagrams, we screened out three catalysts, N3-Ni-Ni-N2, N3-Co-Ni-N2, and N3-Ni-Co-N2, to further study the activity of nitrogen reduction reaction (NRR). The results display that N3-Co-Ni-N2 is a promising NRR catalyst with a relatively low ΔG of 0.49 eV and slow kinetics of the competing hydrogen evolution. This work proposes a new strategy to guide DAC experiments more precisely: the analysis of the surface occupancy state of the catalysts under electrochemical conditions should be performed before activity analysis.
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