Role of transport polarization in electrocatalysis:A case study of the Ni-cluster/Graphene interface

• 作 者: Fang Bian XinGe Wu ShanShan Li GaoWu Qin XiangYing Meng Yin Wang HongWei Yang
• 机 构: School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;College of
• 出 处: 材料科学技术（英文版）
• 发表日期: 2021年33期
• 关键词: First-principles calculations electrocatalysis non-equilibrium electron injectio

As cathodes,iron-series(Fe,Co,Ni)clusters supported by carbon materials exhibit outstanding electrocat-alytic reduction activities in many electrocatalytic applications.To date,this general characteristic of iron-series clusters that should be related to the inherent attributes of these electrodes has not been fully un-derstood from the perspectives of thermodynamics and electronic structure alone.Electron transport is a necessary process in electrocatalysis,and therefore,the study of the change of the electronic state in elec-tron transport is beneficial for understanding this general characteristic of iron-series cluster catalysts.In this work,the electron transport properties,including the conductivity and transport spin-polarization at the Ni-cluster/graphene interface are carefully investigated as an example of carbon-supported iron-series electrodes.Using first-principles calculations within the framework of the nonequilibrium Green\'s func-tion density functional theory(NEGF-DFT),we reveal that the electronic transport states of the coupled Ni-cluster/graphene are strongly changed compared to those of their isolated Ni-cluster and graphene component.It is found that graphene dominates the overall conductivity of the interface,while the mor-phology of Ni-clusters controls the spin polarization efficiency.High spin polarization can lead to the self-excitation effect of the electrons that raises the energy of the electronic system,improves the ther-modynamics of the reduction reaction and promotes catalytic activity.Our work hints that iron-series elements(Fe,Co,Ni)based electrodes may generally show transport polarization that is likely to give rise to a high electrocatalytic reduction activity and such transport polarizability can be used as a new factor in the further exploration and design for electrocatalytic materials.