Doubly doped graphene as gas sensing materials for oxygen-containing gas molecules: A first-principles investigation

Abstract

Recently, defective graphene (DG) are being highly studied nanosheet as a gas sensor. To investigate the adsorption behavior of oxygen containing gas molecules such as CO, NO, NO2 and SO2 on the pristine graphene (PG) and dual B, N, O and F doped DG (2B-DG, 2N-DG, 2O-DG and 2F-DG) nanosheets, density functional theory (DFT) has been carried out. In this study, the DG shows efficient sensitivity towards the gas molecules at the defected site compared with the PG. The adsorption energy, charge transfer and electronic properties indicate that the chemisorption of NO and NO2 on 2B-DG; NO2, SO2 and CO on 2N-DG; NO2, SO2 and CO on 2O-DG; and CO, NO, NO2 and SO2 on 2F-DG take place at the defected sites. Other gas molecules are adsorbed on the nanosheets in a weak physical adsorption process. Although 2F-DG interacts with the gas molecules in high adsorption energies, it is not suitable for gas adsorption due to high recovery time, high formation energy and large structural deformation. Therefore, 2B-DG, 2N-DG and 2O-DG nanosheets could be more promising candidates than PG and 2F-DG for oxygen containing toxic gas molecules.