氧气在碳化钨负载的铜-金合金单层上吸附与解离的第一性原理研究  

First-principles research of oxygen adsorption and dissociation on copper-gold alloy monolayer supported on tungsten carbide

作　　者：常青芳 张喜林 CHANG Qing-Fang;ZHANG Xi-Lin(Henan Key Laboratory of Photovoltaic Materials,School of Physics,Henan Normal University,Xinxiang 453000,China)

机构地区：[1]河南师范大学物理学院河南省光伏材料重点实验室,新乡453000

出　　处：《原子与分子物理学报》2022年第4期7-14,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(11904084,U2004212)。

摘　　要：采用基于密度泛函理论的第一性原理方法研究了碳化钨负载的铜-金合金单层催化剂对氧气吸附和解离性质的影响.通过比较碳化钨负载的纯金单层与铜掺杂的合金单层的电荷布局,发现掺杂铜可以创造新的活性位点,改变氧气的吸附构型,改善氧气的吸附和解离性质.进一步探究了氧气在Cu_(1)Au_(8)/WC(0001),Cu_(2)Au_(7)/WC(0001)上的解离过程,发现:氧气在Cu_(2)Au_(7)/WC(0001)上解离势垒仅为0.64 eV,远低于在纯金单层上的1.56 eV,表明铜掺杂有效促进了氧气的解离.铜掺杂后的单层结构变化预示了在单层产生了配位效应和局部应力效应.电荷布局和态密度结果表明铜掺杂促进了单层上电荷的重新分布,加强了氧气分子与基底的电荷转移和轨道杂化,从而增强了对氧气的吸附.当前的研究结果阐明了碳化钨负载合金单层对氧气分解的促进作用和机理,为设计更加高效廉价的氧还原反应催化剂奠定理论基础.Using the first-principles method based on density functional theory,the effect of copper-gold alloy monolayer supported on tungsten carbide on the properties of oxygen adsorption and dissociation are comparatively studied.Comparing the charge distribution of pure gold monolayer and gold monolayer doped with copper supported on tungsten carbide,it is found that copper doping is beneficial to enhance oxygen absorption and promote oxygen dissociation.We further explored the dissociation pathways of oxygen on Cu_(1)Au_(8)/WC(0001)and Cu_(2)Au_(7)/WC(0001),and found that the dissociation barrier of oxygen on Cu_(2)Au_(7)/WC(0001)is only 0.64 eV,which is much lower than that on pure gold monolayer(1.56 eV).This phenomenon indicates that copper substitution could effectively promote the dissociation of oxygen.The results of charge population and density of states show that copper doping could accelerate the redistribution of electrons on the monolayer,promote charge transfer and orbital hybridization between oxygen molecule and the substrate,and thus enhance the adsorption of oxygen.The current research clarifies the promotion effect and mechanism of the alloy monolayer on oxygen dissociation.

关 键 词：碳化钨 合金单层 氧解离 第一性原理 

分 类 号：O65[理学—分析化学]