Adsorption of CO, NO, and NH3 on ZnO monolayer decorated with noble metal (Ag, Au)

The stable adsorption configuration, electronic structure and magnetic property of CO, NO, and NH3 adsorbed on pristine and noble metal (Ag, Au) atom decorated ZnO monolayer (ZnO-ML) are investigated using density functional theory (DFT). The results show that all three kind of gas molecules are physically absorbed on pristine ZnO-ML during the exothermic process. At the same time, the adsorption performance of the ZnO-ML is enhanced by doping noble metal (Ag, Au) atoms. Both Ag and Au atom doping can greatly enhance adsorption ability of the ZnO-ML to the CO and NO molecules, except for the NH3 molecules. For NO molecules, the adsorption energies of NO on the Ag, and Au atom decorated ZnO-ML are −0.92 eV and −1.30 eV, respectively, which are over 5 and 7 times larger than that of NO on the pristine ZnO-ML, respectively. Therefore, both the Ag, and Au atom decorated ZnO-ML are more sensitive for CO and NO molecules contrast to the ZnO-ML. These results provide insight into the adsorption properties of ZnO-ML, which could promote the further application of ZnO materials in the gas sensing field.