▎ 摘　　要

This work is devoted to an investigation on the carbon dioxide (CO2) sensing properties of pristine graphene (PG), vacancy defect graphene (VG), Stone-Wales defect graphene (SWG), and Pd-doped graphene (PdG), based on density functional theory. To do so, we first relax all the models sufficiently to select the appropriate adsorption configuration and the results show that CO2 molecule reacts weakly on PG and SWG, while strong interaction occurs on VG and PdG. Then, the response to the CO2 molecule of all the graphene-based substrates, in terms of charge transfer, density of states and band structure are examined. To account for the effects of defects and doping on adsorption, we have made the evaluation, for different systems, while before and after adsorbing CO2 molecule. Our results demonstrate that vacancy defect and Pd doping can significantly enhance the response of graphene to CO2 molecule with the optimum adsorption energy of -1.76 eV and -4.63 eV, respectively, and thus indicate that VG and PdG may be used as CO2 sensing materials.