The adsorption behaviors of NO on penta-graphene and Ni-doped penta-graphene.

In order to develop the adsorption application of penta-graphene (PG) to NO gas molecule, we calculated the sensing properties of PG and Ni-doped PG to NO molecule first-principles calculations. Based on the calculated adsorption energy, charge transfer, band gap, density of states and partial density of states, we observed that this gas molecule was weakly physically adsorbed on the surface of intrinsic PG, while the adsorption behaviors on the surface of Ni-doped PG were greatly influenced by the doping sites and adsorption orientations. With the Ni atom doped at the sp hybridized carbon site, strong chemical adsorption between the gas molecule and the substrate was induced. The adsorption structure of the NO molecule with its N atom close to the substrate exhibited better stability. Moreover, an external perpendicular electric field could enhance the adsorption performance of the NO molecule and adjust the charge transfer between the molecule and substrate. Our results broaden the adsorption applications of PG and indicate that Ni-doped PG is a potential candidate for NO gas sensors.