▎ 摘　　要

We predict the CO2, NO, NO2 and SO2 gas molecule absorption and sensing performance of transition metal (Fe, Ni, Co and Cu) doped graphene by a systematic density functional theory (DFT) study. Our results demonstrate that graphene doped with different transition metal atoms produces completely different adsorption behaviors of small gas molecules originated from changes in the electronic structure of the systems under strain. Graphene doped with Fe atoms was the best platform for sensing NO2 gas molecules (NO2/Fe-MG). The NO2/Fe-MG system showed the best adsorption rate, the higher charge transfer and the shortest distance between the graphene platform and the gas molecule of all the calculated systems. As the strain increases, the adsorption energy and charge transfer decreases. So the NO2 gas molecule adsorption properties of Fe-MG without strain would help in guiding experimentalists to develop better materials based on graphene for efficient gas detection or sensing applications.