Hydrogen sulfide gas detection by Au-decorated ZnO nanotube: a computational study and comparison to experimental observations

Abstract

Based on the experimental reports, Au-decoration on the ZnO nanostructures dramatically increases the electronic sensitivity to H₂S gas. In the current study, we computationally scrutinized the mechanism of Au-decoration on a ZnO nanotube (ZON) and the influence on its sensing behavior toward H₂S gas. The intrinsic ZON weakly interacted with the H₂S gas with an adsorption energy of −11.2 kcal/mol. The interaction showed no effect on the HOMO–LUMO gap and conductivity of ZON. The predicted response of intrinsic ZON toward H₂S gas is 6.3, which increases to 78.1 by the Au-decoration at 298 K. The corresponding experimental values are about 5.0 and 80.0, indicating excellent agreement with our findings. We showed that the Au atom catalyzes the reaction 3O₂ + 2H₂S → 2SO₂ + 2H₂O. Our calculated energy barrier (at 298 K) is about 12.3 kcal/mol for this reaction. The gap and electrical conductance Au-ZON largely changed by this reaction are attributed to the electron donation and back-donation processes. The obtained recovery time is about 1.35 ms for desorption of generated gases from the surface of the Au-ZON sensor.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electronic properties
• ZnO nanostructures
• density functional
• gas sensor

Acknowledgements

This work was supported by Doctoral Research Initiation Fund Project of Jilin Engineering Normal University (BSKJ201914), Research and Development Fund Project of Jilin Engineering Normal University (2019hx62kj).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Doctoral Research Initiation Fund Project of Jilin Engineering Normal University [grant number BSKJ201914], Research and Development Fund Project of Jilin Engineering Normal University [grant number 2019hx62kj].