1. Surface reactions of CH3OH, NH3 and CO on ZnO nanorod arrays film: DFT investigation for gas sensing selectivity mechanism.
- Author
-
Yang, Tingqiang, Jin, Wei, Liu, Yueli, Li, Hang, Yang, Shuang, and Chen, Wen
- Subjects
- *
NANORODS , *METAL oxide semiconductors , *DENSITY functional theory , *ABSORPTION , *ELECTRONS - Abstract
The obscurity in selectivity mechanism has resulted in dilemmas in the research of selectivity properties of metal oxide semiconductor (MOS) gas sensing materials. In this work, selectivity mechanism of ZnO nanorod arrays to CH 3 OH is revealed by systematically simulating response and recovery reactions of three gas molecules (CH 3 OH, NH 3 and CO) based on density functional theory (DFT). Results suggest that selectivity to CH 3 OH is due to three factors: i. Response reaction of CH 3 OH on ZnO (1 0 1 - 0) is most exothermic, which is main reason for the selectivity against NH 3 . ii. Intermediates as well as products oxidized from CH 3 OH have strongest absorption ability, which hinders reabsorption of O 2 molecule, mainly leading to selectivity against CO. iii. H adatoms dissociated from CH 3 OH transfer most electrons to ZnO surface layers, which is also responsible for the selectivity. This work provides a new insight into selectivity mechanism and a practicable method to predict selectivity properties of MOSs. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF