▎ 摘　　要

The adsorption mechanisms of small gases on CoNx (x = 2,3,4) embedded graphene surfaces are investigated using DFT calculation. Focusing Bader charge analysis, charge density difference, Density of State for surface analysis and partial density of state, the gas activities (CO, CO2, NO, NO2, NH3 and O2) are studied in Quantum Esspresso software with Van der Waals correction. The adsorption energy, charge transfer, gas height from the surfaces, bond lengths, and magnetic momentum are calculated to understand the gas adsorption mechanisms. Doping nitrogen to graphene surface changes the gas adsorption system. Doping/removing nitrogen to/ from the surface can increase the stability of gas on the modified graphene sheet. The study exhibits that the most stable gas is NO2 on CoNx graphene with chemical interaction. The weak interactions are observed on NH3 and CO2 molecules. These modified graphene sheets are promising materials as gas sensors.