Adsorption behavior of NO2 molecules in ZnO-mono/multilayer graphene core-shell quantum dots for NO2 gas sensor

We demonstrated the sensing properties and adsorption mechanism of NO2 molecules of monolayer graphene and multilayer graphene encapsulated ZnO QDs for NO2 gas adsorption. The gas response value of ZnO-multilayer graphene (ZMLG) QDs was approximately 23 % and 7.2 and 25.5 times higher than that with ZnO-monolayer graphene (ZG) and ZnO QDs, respectively. The surface potential change of ZMLG QDs increased up to 14.25 times compared to ZnO QDs and 6.33 times increased compared to ZG QDs. We proposed an accurate adsorption mechanism for the improvement of the detection behavior that is occured by covering the graphene shells into ZnO QDs by the Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and SKPM measurement. These results are expected to increase the accuracy of gas sensor characteristic analysis. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

This study demonstrates the sensing properties and adsorption mechanism of monolayer graphene and multilayer graphene encapsulated ZnO quantum dots for NO2 gas. The results show that the gas response value and surface potential change of multilayer graphene encapsulated ZnO quantum dots are significantly higher than those of monolayer graphene and ZnO quantum dots. The proposed adsorption mechanism provides insights for improving the detection behavior and enhancing the accuracy of gas sensor analysis.