Indium-doped and positively charged ZnO nanoclusters: versatile materials for CO detection. (January 2018)

• Record Type: Journal Article
• Authors: Omidvar, Akbar
• Is Part Of: Vacuum. Volume 147(2018)
• Page Start: 126
• Page End: 133
• Publication Date: 2018-01
• Subjects: ZnO nanocluster -- CO detection -- Sensor -- Density functional theory; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2017.10.023
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Indium-doped ZnO nanoparticle has been recently synthesized using a modified sol-gel technique. This study has revealed that the In-doped ZnO nanoparticles represent a higher sensitivity than the pristine ZnO nanoparticles to the carbon monoxide gas and can detect it at sub-ppm concentrations. Motivated by this study, in the present work using first-principles calculations, we study the effect of In-doping on the sensing properties of a ZnO nanocluster. In our survey, we have explored the sensitivity of pristine as well as In-doped ZnO nanoclusters towards CO detection. In contrast to the pristine form, the In-doped ZnO nanocluster can detect the CO molecule due to significant decrease in the HOMO-LUMO energy gap and thereby in the resistivity. As a secondary objective of the present study, electrical charging of the ZnO nanocluster is proposed as an approach for electrocatalytically switchable CO adsorption. We found that the CO molecule is weekly adsorbed on the neutral ZnO nanocluster. Our results show that the interaction between CO molecule and ZnO nanocluster is dramatically increased by introducing extra positive charges into the nanocluster. Once the charges are removed, the CO molecule spontaneously desorbed from the ZnO absorbent. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Graphical abstract: The sensitivity of pristine, charged and In-doped nanoclusters towards CO detection. Highlights: The CO adsorption on the pristine, In-doped, and charged ZnO nanocluster. The sensitivity of ZnO nanocluster to CO can be remarkably increased by In-doping. The CO adsorption/release occurs by switching on/off charge-carrying states.