DFT study of small gas molecules (C2H2, CH4, CO and H2) adsorbed on Au, Ag-doped ZnO monolayer

In this paper, the interactions of small gas molecules (C2H2, CH4, CO and H2) with pure ZnO, Ag-ZnO and Au-ZnO monolayer were investigated using DFT calculations to explore their potential applications as gas sensing. Among them, the adsorption effect on C2H2 and CH4 was better with an increase of 1 eV in adsorption energy, and the adsorption effect of other gases was improved (CO:-0.63 eV to-1.03 eV, H2:-0.68 to-1.44 eV). The increase in adsorption energy was explained by parameters such as charge transfer, density of states and work function. Meanwhile, intrinsic ZnO is unsuitable for gas detection and adsorption, while the Au-ZnO monolayer suits C2H2, CH4, CO and H2 detection. The electrical conductivity of the adsorption models is changed to varying degrees after gas adsorption. The research results act as a theoretical foundation for constructing gas sensors with a ZnObased material.