Indexed by:会议论文

Date of Publication:2016-10-20

Included Journals:EI

Volume:898 MSF

Page Number:1947-1959

Abstract:It is necessary to develop NO2gas sensors as NO2is a pollutant. While, different from the reducing gases, oxidizing gas NO2will put up a complicated sensing process. Density functional theory (DFT) calculations are necessary to be performed to understand NO2-sensing mechanisms at the atomic level. In this study we introduce NO2to SnO2(110) surface with oxygen species pre-adsorbed. The results show that NO2sensing mechanism of SnO2surface strongly depends on the concentration of oxygen in the ambient atmosphere (usually, no effects of temperature and pressure are considered). The direct interactions between NO2molecule and SnO2sub-reduced surface (with two rows of fold-coordinated bridging oxygens removed) for very low oxygen concentrations show that, NO2gas molecules interact directly with Sn instead of reacting with oxygen species, resulting in an increase in resistance of SnO2. We investigate gas-sensing processes of interaction between NO2molecule and SnO2surface with pre-adsorbed oxygen species for the case of considerable high oxygen concentrations. Adsorbed molecular oxygen ions compete with adsorbing NO2molecules for available surface sites and electrons from the SnO2. As the availability of oxygen ions on the SnO2surface increasing, the interaction between NO2and adsorbed oxygen species give rise to a reducing interaction, which brings a decrease in resistance of SnO2. © 2017 Trans Tech Publications, Switzerland.