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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。
As a sensitive material of the sensor, TiO2 has the unique advantages of high sensitivity, fast response time and low working temperature, so it has received extensive attention. In this paper, based on the first-principle planar super-soft pseudopotential method based on density functional theory (DFT) framework, CASTEP software package was used to simulate the adsorption distance of NO2 adsorbed on the anatase TiO2 (101) Electronic density of states and optical properties. The results show that NO2 adsorbed on the surface of the anatase-type TiO2 (101) and one oxygen vacancy-defective surface have the most stable structure on the O-side. The surface of NO2 , The adsorption energy is larger than that of the anatase TiO2 (101) surface. The adsorption process is exothermic. When the NO2 molecule adsorbs on the surface containing 1 oxygen vacancy defect, the absorption of low energy part of visible light is better, Absorption and reflection properties of the significant changes in the optical gas sensor performance characteristics significantly, in order to detect the exhaust gas vehicle NO2 content. The research provides a theoretical basis for the laboratory research on the detection of harmful gases from automobile tail gas by using anatase TiO2 as a sensitive sensor material.