CePO_(4)低指数晶面结构性质的密度泛函理论研究  

A Density Functional Theory Study on Structural Properties of CePO_(4)Low Index Crystal Plane

作　　者：张露 罗慧娟 武文斐[1,2] 张凯 Zhang Lu;Luo Huijuan;Wu Wenfei;Zhang Kai(School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China;Key Laboratory of Effi-cient and Clean Combustion,Baotou 014010,China)

机构地区：[1]内蒙古科技大学能源与环境学院,内蒙古包头014010 [2]内蒙古自治区高效洁净燃烧重点实验室,内蒙古包头014010

出　　处：《中国稀土学报》2022年第4期672-680,共9页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51866013/22068029);内蒙古自然科学基金资助项目(2019ZD13)资助。

摘　　要：采用密度泛函理论系统研究了CePO_(4)三个低指数晶面的几何结构、原子弛豫和表面能。通过观察表面结构以及比较表面能大小得出最优晶面。结果表明:表面原子均存在不同程度的弛豫,表面原子弛豫程度导致表面能的差异。表面能的大小顺序为(010)<(100)<(001),(010)晶面是CePO_(4)晶体稳定表面。稳定表面几何结构表明,终止末端暴露原子为O原子。使用Wulff结构计算的平衡形态表明(001)晶面、(010)晶面和(100)晶面面积分别占总晶体形状面积的14%,45%和41%。低能表面在Wulff结构中起主导作用,表面能越低的晶面面积占比越大。稳定的CePO_(4)晶面存在不饱和键,有利于气体分子的吸附。这项工作对CePO_(4)在其他方面的密度泛函理论(DFT)研究具有指导性意义,并将为CePO_(4)基催化剂上的吸附和解离提供稳定表面。In this paper,density functional theory is used to systematically study the geometric structure,atom⁃ic relaxation and surface energy of three low-index surfaces of CePO_(4).By observing the surface structure and comparing the surface energy,the optimal surfaces could be obtained.The results show that surface atoms all have different degrees of relaxation and the degree of relaxation of surface atoms leads to the difference in sur⁃face energy.The surface energy is in the order(010)<(100)<(001),and the(010)surface is the most stable surface of CePO_(4)crystal.The stable surface geometry indicates that the exposed atom at the termination end is an oxygen atom.The equilibrium morphology calculated with the Wulff structure shows that(001)surface,(010)surface and(100)surface account for 14%,45%and 41%of the total crystal shape area,respectively.The low-energy surface plays a leading role in the Wulff structure.The lower the surface energy is,the larger the proportion of the area is.The optimized CePO_(4)surface has unsaturated bonds on the surface,which is condu⁃cive to the adsorption of gas molecules.This work has guiding significance for the density functional theory(DFT)study of CePO_(4),and will provide a stable surface for gas adsorption and dissociation on CePO_(4)-based cat⁃alysts.

关 键 词：CePO_(4) 表面能 稳定表面 密度泛函理论计算 

分 类 号：TQ133.3[化学工程—无机化工]