锐钛矿相TiO_(2)(101)表面对有机分子不同官能团微观吸附的机制  

Mechanism of microscopic adsorption of organic molecules with different functional groups on the surface of anatase phase TiO_(2)(101)

作　　者：高鑫[1,2] 冯庆 付岳[1,2] 牟芷瑶 潘一翠 GAO Xin;FENG Qing;FU Yue;MOU Zhi-Yao;PAN Yi-Chui(College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 40131,China;Chongqing Key Laboratory of Optoelectronic Engineering,Chongqing 401331,China)

机构地区：[1]重庆师范大学物理电子工程学院,重庆401331 [2]重庆市光电工程重点实验室,重庆401331

出　　处：《原子与分子物理学报》2023年第5期25-32,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(61274128);重庆自然科学基金(csts2019jcyj-msxm0953);重庆市教委项目(kjqn201800510)。

摘　　要：挥发性有机化合物(VOCs)严重危害了生态环境和人体健康,因此对具有典型官能团的VOCs气体进行灵敏检测具有重要意义.文章研究了具有典型官能团的VOCs气体C_(2)H_(2)、C_(2)H_(4)、HCOOH、CH_(3)OH、HCHO和CH_(3)COCH_(3)分子在锐钛矿相TiO_(2)(101)表面吸附的传感特性.结果表明:具有氧空位缺陷的表面对极性分子吸附时,偶极矩越大,吸附体系越稳定;对非极性分子吸附时,C原子成键饱和程度越低,吸附体系越稳定.分析发现,差分电荷密度和电荷布局体现出偶极矩大小和C原子成键饱和程度对气体分子得失电子能力的影响.对于极性分子,气体分子官能团中O原子得到电子的能力为OCH_(3)COCH_(3)>OHCHO>OCH_(3)OH>OHCOOH;对于非极性分子,官能团中C原子得到电子的能力为CC_(2)H_(2)>CC_(2)H_(4).态密度图分析发现吸附体系在费米能级处的峰值位置和大小也受到偶极矩与C原子饱和度的影响,其本质原因是不同官能团与材料表面的氧化还原能力不同.因此,材料表面的吸附稳定程度与极性分子的偶极矩或非极性分子的C原子成键饱和程度密切相关.通过研究气体的偶极矩和C成键饱和程度对探索材料对有机气体的吸附性气敏传感有重要的意义.Volatile organic compounds(VOCs)seriously endanger the ecological environment and human health,so it is of great significance to detect VOCs gases with typical functional groups.In this paper,the sensing properties of VOCs gas C_(2)H_(2),C_(2)H_(4),HCOOH,CH_(3)OH,HCHO and CH_(3)COCH_(3) molecules with typical functional groups on the surface of anatase TiO_(2)(101) were investigated.The results show that when the surface with oxygen vacancy defects adsorbs polar molecules,the larger the dipole moment is,the more stable the adsorption system is;when the surface with oxygen vacancy defects is adsorbed on non-polar molecules,the lower the saturation degree of C atom bonding,the more stable the adsorption system.The analysis shows that the differential charge density and charge layout reflect the influence of the size of the dipole moment and the degree of C atom bond saturation on the ability of gas molecules to gain or lose electrons.For polar molecules,the ability of the O atom in the functional group of the gas molecule to gain electrons is OCH_(3)COCH_(3)>OHCHO>OCH_(3)OH>OHCOOH.For non-polar molecules,the ability of the C atom in the functional group to gain electrons is CC_(2)H_(2)>CC_(2)H_(4).The analysis of the density of states diagram reveals that the peak position and size of the adsorption system at the Fermi energy level are also influenced by the dipole moment and the saturation of C atoms,which is essentially due to the different redox ability of different functional groups with the material surface.Therefore,the degree of adsorption stability on the surface of the material is closely related to the dipole moment of polar molecules or the degree of bond saturation of C atoms of non-polar molecules.It is of great significance to explore the adsorption gas sensing of organic gases by studying the dipole moment of the gas and the degree of C bond saturation.

关 键 词：VOCS 密度泛函理论 锐钛矿相 官能团 第一性原理 

分 类 号：O472[理学—半导体物理]