▎ 摘　　要

Two-dimensional materials have shown desirable application prospects in the field of gas sensing. Through the modification of graphene gas-sensitive materials, more efficient and sensitive gas sensors can be further devel-oped. The use of metal atoms or oxygen-containing groups to modify graphene can improve its detection per-formance for gases. Modified-graphene could be selected as an excellent gas sensor for poisonous gas detection. In this work, adsorption systems of CNCl, NH3 and GB on metal doped graphene (Au, Ag, Cu and Fe) and gra-phene oxide were established by the using of density functional theory (DFT). The adsorption energy, charge transfer, DOS, PDOS and energy band of these adsorption systems were investigated. The gas adsorption strength and gas selectivity factor were introduced to evaluate the selectivity of each substrate to these harmful gases in O2 and N2 environments. The calculation shown strong adsorption between the metal-doped graphene and the adsorbed gas, with Fe-doped graphene having better adsorption performance. By contrast, between graphene oxide and the adsorbed gas, the effect was slight. Moreover, the energy band change of metal-doped graphene was more obvious than that of graphene oxide. In addition, under O2 and N2 environment, Au-doped graphene may have good selectivity for CNCl and NH3 while Ag-doped graphene may have good selectivity for GB. This result will provide reference for the development of graphene based gas sensors for CNCl, NH3 and GB.