First principles studies of adsorption of H2S on vacancy defected and transition metal-doped phosphorene-graphene heterostructures

Abstract

The adsorption stability, geometry, and electronic and magnetic properties of H2S adsorbed on pristine, vacancy defected, and transition metal (TM)-doped phosphorene-graphene (PG) heterostructures were calculated using density functional theory. In pristine and vacancy defected PG systems, the interaction between H2S and the heterostructure was weak, and the mechanism was physical adsorption. After TM-doping (Ti, V, Cr, Mn, Co, and Ni), the strong orbital hybridisation between the dopant and H2S significantly enhanced the interaction between H2S and the doped heterostructures, and the physisorption mechanism of H2S changed to chemical adsorption. The adsorption energy and desorption time of H2S molecules on Mn-doped PG heterostructures was suitable, which can be applied as sensors to detect H2S gas. The density of states of Cr- and Mn-doped PG heterostructures exhibited asymmetric electron spin states, indicating the existence of magnetic moments. Thus, introducing defects and TM dopants on PG heterostructures can improve H2S sensitivity, providing a theoretical basis for developing gas detection sensors.