Mechanism of CO and acetone adsorption on ZnO and Pt-doped ZnO surfaces for gas sensing applications: A DFT investigation

Spin-polarized density functional theory (DFT) is employed to explain the role of oxygen vacancy, pre-adsorbed oxygen ion, and Pt dopant in CO and acetone sensing of ZnO (0001) surface. Adsorption configurations and electronic properties of ZnO and Pt-doped ZnO surfaces are reported. The results show that good adsorption energy is not alone enough to judge the sensitivity of gas sensors, and one has to consider all charge transfer modes. Charge density difference plots reveal that there is a charge transfer mode for moving electrons from acetone to pre-adsorbed oxygen ion which means that the the direct adsorption of acetone may have a chance to participate in gas sensing also.

Automated summary

Spin-polarized density functional theory was used to explore the role of oxygen vacancy, pre-adsorbed oxygen ion, and Pt dopant in CO and acetone sensing on the ZnO surface. It was found that good adsorption energy alone is not enough to determine sensor sensitivity, as all charge transfer modes must be considered. Charge density difference plots revealed a charge transfer mode from acetone to pre-adsorbed oxygen ion, suggesting that direct adsorption of acetone may also play a role in gas sensing.