Enhanced Adsorption of SO2 Molecule on Al- and Si-Doped Pyridinic Nitrogen Doped Graphene

Abstract

The adsorption properties of SO₂ molecule on the surface of pyridinic nitrogen doped graphene (4NG), M/4NG and M/2NG (M = Al, Li, Si) are investigated using density functional theory. The adsorption energies have been calculated for the most stable configurations of the molecule on the surface of 4NG, M/4NG, and M/2NG. It is found that M/4NG (M = Al, Si) have significant adsorption energies than that of pyridinic nitrogen doped graphene and M/2NG (M = Al, Si). The doped Li atom did not enhance the interactions between the 4NG and SO₂. Furthermore, connecting distance and net electron transfers give the evidence that the SO₂ stay on M/4NG (M = Al, Si) by chemisorption. Significant changes in density of states (DOS) show the existing of noteworthy orbital hybridization between SO₂ and M/4NG–SO₂ (M = Al, Si) during adsorption process which is proving to strong interaction while there is no evidence for hybridization between the SO₂ molecule and 4NG. Compared with 4NG, Al/4NG, and Si/4NG may be promising adsorbent for practical applications.