[en] Highlights: • Doping transition metal atoms (Zr, Mo, Ti, Mn, Fe, Co) can change the electronic properties of graphene sheet system. • The Mn-doped graphene sheet exhibits the strongest adsorption effect for the phosgene molecule. • The electronic and optical properties of TM-doped graphene are significantly changed upon phosgene adsorption. • Mn-doped graphene is theoretically predicted to be a potential sensor and scavenger of phosgene. - Abstract: The adsorption of the phosgene molecule on pristine graphene and transition metal doped (TM = Zr, Mo, Ti, Mn, Fe, Co) graphene is investigated using the first principles method based on density functional theory. The nature of interaction between the phosgene molecule and pristine graphene or transition metal doped graphene (TM-doped graphene) is discovered by geometries, adsorption energies, Mulliken charge distribution, density of states analysis and UV spectrum. Computational results show that the interaction between the phosgene molecule and pristine graphene is a weak physisorption. But doping with transition metals results in stronger chemical adsorption. This is due to the formation of a chemical bond between the metal atom and oxygen atom of phosgene, which makes TM-doped graphene really promising material for phosgene removal. TM-doped graphene also exhibits different electronic properties after adsorbing phosgene, compared with pristine graphene. Furthermore, the calculations reveal that UV spectrum of the TM-doped graphene is modified by the phosgene adsorption. Thus, the significant variations in electronic and optical properties of the TM-doped graphene sheet as interacting with the phosgene can be utilized to detect the phosgene.