Ab initio study on gas sensing properties of group III (B, Al and Ga) doped graphene

The adsorptions of small gas molecules (CO, NO and NO2) on group III (B, Al and Ga) doped graphene are investigated using ab initio density functional theory calculations, to exploit the potential applications of graphene as toxic gas sensors. For enabling practical gas sensing applications, the effect of water vapour on the sensing properties of these doped graphenes are also studied. The most stable geometries of gas molecules on these doped graphenes are determined and the adsorption energies are calculated. Our results show that the structural and electronic properties of B-doped graphene are sensitive to NO and NO2, but not influenced by the adsorption of CO and H2O. The chemisorptions of CO, NO, NO2 and H2O on Al- and Ga-doped graphene were evident from large adsorption energies, large charge transfers and were confirmed by analysis of band structures and density of states. Hence Al- and Ga-doped graphenes can be used as good sensors for detecting CO, NO and NO2. The calculations also indicate that B-doped graphene can be used as an excellent gas sensing platform for detecting NO and NO2, whereas Al- and Ga-doped graphene may not be suitable choices for harmful gas detection, in the presence of water vapour.