▎ 摘　　要

Following an experimental work, density functionals B3LYP, TPSS, PBE, M06-2X, and omega B97X-D were exploited to examine the impact of decorating an Ag atom on a ZnO nanosheet sensitivity to the ethanol gas. The interaction of the pristine ZnO sheet with the ethanol was found to be weak, and the sensing response is 6.2 at 300 K based on the B3LYP results, in agreement with experiment. Decorating an Ag atom on the ZnO sheet increases the adsorption energy of ethanol from - 6.1 to - 20.0 kcal/mol. Energy decomposing analysis indicates that the interaction converts from noncovalent to covalent by the Ag decoration. Also, the sensing response significantly rises to 72 (experimental value similar to 55). We showed that the Ag decorated ZnO sheet can selectively detect ethanol gas in the presence of benzene, formaldehyde, toluene, and acetone. A short recovery time of 35 s is found, being comparable with experimental value of 25 s. We introduced a theoretical methodology which can reproduce the experimental results. Both theory and experiment suggest that Ag-decorated ZnO nanosheet may be highly sensitive and selective ethanol sensor with a short recovery time.