▎ 摘　　要

The effects of the absorption of the gas molecule on the work function and the field emission current of graphene have been theoretically investigated. The results demonstrate that the absorbed O-2, CO, and H-2 on graphene with different absorption and absorption types have a large effect on its field emission properties. All absorbed O-2, CO, and H-2 on graphene with different absorption sites and absorption types except H-2 on the bridge site lead to a reduction in its field emission current. It agrees with the experimental conclusion that the adsorption of O-2 on the graphene will reduce its field emission current in the literature. Numerical results suggest that the density of adsorbed molecules, the types of adsorbed molecules, the type of adsorption and the location of adsorption could be detected by measuring the variation rule of the field emission current under different applied electric fields. This implies that the characteristics of field emission properties of graphene can be implemented as a working principle of a feasible gas sensor.