▎ 摘　　要

First-principles DFT calculations were applied to investigate the adsorption of the XO2 (X = C, S or N) molecule on the pure graphene or the graphene doped with a Ta atom. The Ta atom could be successfully doped into the graphene sheet with a high binding energy of - 5.562 eV. The CO2, SO2 or NO2 interacted weakly with the pure graphene whereas was strongly adsorbed on the Ta-doped graphene with high adsorption energy of - 0.952, -1.684 or - 2.316 eV, respectively. There were 0.61 e (0.38 e or 0.42 e) transferred to the adsorbed NO2 (SO2 or CO2) from the Ta-doped graphene, indicating the high selectivity performance of the modified graphene towards the NO2. Moreover, there were four NO2 molecules in maximum chemically adsorbed on the Ta-doped graphene. The research indicates that the Ta-doped graphene is promising to exhibit outstanding and selective adsorption/sensing performance towards the NO2 gas.