▎ 摘　　要

Single-atom catalysts have become a hot topic in chemical industry and environmental engineering recently, which put stress on the studies of stability and catalytic activity of single-atom catalyst with nanomaterial substrate. In this study, the stability of Mn/GS and the adsorption behaviors of NO2, NO and NH3 are discussed through density functional theory calculations. We found that the order of the support effect of different Mn/GS was Mn/SV-GS > Mn/DV-GS > Mn/SW-GS > Mn/In-GS. Besides, the results of adsorption energies and bond lengths showed that the catalytic oxidation of NOx by Mn/GS was realized through activating N-O bond of NO2, while Mn/GS mainly played support effect in adsorption of NO and NH3. Moreover, electron transfer mechanisms of NO2, NO and NH3 adsorbed on Mn/GS are investigated. NO2 and NO act as the electron adopters while NH3 act as the electron donor in the adsorption system. At last, DOS and PDOS calculations were done to confirm the bond formation between N atom and Mn atom. These findings explored the catalytic activity and stability of NOx and NH3 in Mn/GS, which provided a guideline for the reaction mechanisms of NOx catalytic oxidation catalyzed by Mn/GS.