论文部分内容阅读
利用光学气敏材料吸附气体来检测气体成分及浓度,成为了大家的一个研究热点.采用基于密度泛函理论(DFT-D)体系下的第一性原理平面波超软赝势方法,研究了含氧空位金红石相TiO_2(110)表面,SnO_2(110)表面和GeO_2(110)表面吸附HCl气体后,表面结构的氧化性能、态密度、电荷分布、差分电荷密度以及光学性质,讨论吸附对光学气敏传感特性的影响.研究发现:HCl气体均易吸附于含氧空位金红石相TiO_2,SnO_2和GeO_2表面;且吸附后的稳定性为:TiO_2>SnO_2>GeO_2;氧化性是影响吸附能力和光学气敏传感性能的重要因素,HCl分子吸附于表面后其氧化性强弱为:TiO_2氧空位>SnO_2氧空位>GeO_2氧空位;从态密度和光学性质分析发现,含氧空位金红石相TiO_2(110)吸附HCl分子后,光学性质的改变最为明显,特别是对于500~700 nm的光,TiO_2具有很好的光学气敏传感效应,可作为一种较为理想的光学气敏传感材料.
It has become a hot research topic to detect the composition and concentration of gas by using optical gas-sensing material to adsorb gas.Using the first-principle plane wave ultra-soft pseudopotential method based on density functional theory (DFT-D) Oxygen vacancies on the surface of TiO_2 (110), SnO_2 (110) and GeO_2 (110) adsorbed on the surface of the rutile TiO2 were investigated. The oxidation, density, charge density distribution, The sensitivities of sensitivities to HCl were investigated. It was found that HCl gas adsorbed on the surface of oxygen vacancies rutile TiO 2, SnO 2 and GeO 2, and the stability of adsorbed HCl was TiO 2> SnO 2> GeO 2. The important factors of the gas sensing performance are as follows: the oxygen vacancy of HCl molecules adsorbed on the surface is: TiO_2 oxygen vacancies> SnO_2 oxygen vacancies> GeO_2 oxygen vacancies. From the analysis of the state density and optical properties, it is found that the oxygen vacancy rutile TiO_2 110) has the most obvious change of optical properties after adsorbing HCl molecules. Especially for the light of 500-700 nm, TiO 2 has good optical gas sensing effect and can be used as an ideal optical gas sensing material .