吸附
氧气
六方晶系
材料科学
机制(生物学)
化学工程
化学物理
纳米技术
化学
物理化学
结晶学
物理
量子力学
工程类
有机化学
作者
Feng Hui Tian,Cong Gong,Rong Wu,Zhenze Liu
标识
DOI:10.1016/j.mtchem.2018.04.004
摘要
Background oxygen play important role in the detection of gases on metal oxide surfaces. In this work, a new mechanism dominated by oxygen density has been proposed based on density functional theory (DFT) calculation of CO adsorption on the oxygen pre-absorbed and oxygen deficient hexagonal WO3 (h-WO3) (001) surface. Taking clean WO-terminated h-WO3 (001) surface as the datum, we can define the O- and WO-terminated h-WO3 (001) surfaces to be situations with surface oxygen density (denoted as dO) of 1 and 0, respectively. And the oxygen density will be positive (1 > dO > 0) for oxygen absorbed surfaces and negative (0 > dO > −1) for oxygen vacancy presented surfaces. More importantly, environmental oxygen concentration can be reflected directly by surface oxygen density. A positive correlation between environmental oxygen concentration (surface oxygen density) and sensing ability (charge transfer number) can be constructed based on the data of CO sensing on h-WO3 (001) surfaces (Zhao et al., 2013; Tian et al., 2014). And these ideas obtained for CO on h-WO3 can also be generalized to other gases and materials. The new proposed oxygen density dominated gas sensing mechanism, combined the two existing models of surface absorbed oxygen and oxygen vacancy together by the use of one physical quantity of oxygen density, will simplify the understanding of the effect of environmental oxygen on gas sensing largely. And the new findings here will provide substantial chances for controllable sensing by surface tuning.
科研通智能强力驱动
Strongly Powered by AbleSci AI