A DFT study on the Ag-decorated ZnO graphene-like nanosheet as a chemical sensor for ethanol: Explaining the experimental observations

•The impact of Ag decorating on a ZnO nanosheet sensitivity to the ethanol gas is studied.•The sensing response of pristine ZnO is 6.2 at 300 K based on the B3LYP results.•Decorating an Ag atom on the ZnO sheet increases the adsorption energy of ethanol.•Also, the sensing response significantly rises to 72 (experimental value ~55).•The Ag decorated ZnO sheet can selectively detect ethanol gas.•A short recovery time of 35 s is found, being comparable with experimental value of 25 s.