锐钛矿型TiO_2(101)表面吸附NO_2微观特性的理论研究  

Study Micro-character Theory on Anatase TiO_2(101) Surface Adsorption of NO_2

作　　者：杨英[1] 冯庆[1] 

机构地区：[1]重庆师范大学物理与电子工程学院,重庆401331

出　　处：《重庆师范大学学报（自然科学版）》2014年第5期120-125,共6页Journal of Chongqing Normal University:Natural Science

基　　金：国家自然科学基金(No.61274128;No.61106129);重庆市自然科学基金(No.CSTC2013JCYJA0731)

摘　　要：TiO2作为传感器的敏感材料具有灵敏度高、响应时间快、工作温度低等独特优点,故而受到广泛重视。本文通过基于密度泛函理论(DFT)框架下的第一原理的平面超软赝势方法,运用CASTEP软件包模拟计算了NO2吸附在锐钛矿型TiO2(101)面的吸附距离、吸附能、电子态密度以及光学性质。通过完整锐钛矿型TiO2(101)面和含有1个氧空位缺陷表面对NO2的吸附计算发现,NO2分子在表面吸附时,以O端吸附结构最为稳定;含有1个氧空位的表面对NO2的吸附能大于锐钛矿型TiO2(101)完整表面;吸附过程为放热过程;NO2分子在含有1个氧空位缺陷表面发生吸附时,对可见光低能部分的吸收率较好,可见光范围内的吸收和反射性质发生明显的改变,光学气敏传感器的特性表现显著,以此来探测汽车尾气中NO2气体的含量。研究为锐钛矿型TiO2作为灵敏传感器材料探测汽车尾气有害气体的实验室研制提供理论基础。TiO_2 has being widely interested because it has higher sensitive, faster response time and lower working temperature. In this paper, energy of adsorption, density of states and optical properties was studied by adopting the first-principles caeulation of plane wave ultra-softpseudo-potential technology based upon the density function theory（DFT）. Through the NO_2 adsorption on the anatase TiO_2 （101） complete surface and the anatase TiO_2 （101） surface containing an oxygen vacancy defeets, we find that when the NOz molecules on the surface adsorption, O-terminal of NO_2 molecules absorbed on the surface is the most stable. And the adsorp- tion energy of NO_2 adsorption on surface containing an oxygen vacancy defects can be greater than complete surface. Adsorption process is exothermic, O-terminal of NO_2 molecules absorbed on the surface is the most stable. When NO_2 adsorption on the sur- face containing an oxygen vacancy defects, the low energy part of the visible light absorption rate is better, absorption and reflection properties have obvious changed within the scope of visible light, the optical characteristics of the gas sensor performance significantly. The anatase TiO_2 as gas sensing materials to detect nasty gas in vehicle exhausts, in order to provide the basic theories for lab.

关 键 词：TIO_2薄膜 气体传感器 NO_2 密度泛函理论 

分 类 号：O482[理学—固体物理] O614[理学—物理]