Optimized geometry, electronic structure and Ag adsorption property of nanosheet graphene with different symmetry shapes: a theoretical investigation

Optimized geometries and electronic structures of three different symmetry shapes of nanosheet graphenes with armchair and zig-zag edges were generated by using the generalized gradient approximation/Perdew-Burke-Ernzerhof (GGA/PBE) method of density function theory (DFT) with the double-zeta polarized (DZP) basis set. Based on the results, the calculated HOMO-LUMO energy gap (Eg = LUMO-HOMO) with different symmetry shapes, and nanosheet size for with zig-zag and armchair edges were also presented. Because the p (pi) orbital was widely localized over the sheet surface, the calculated E (g) decreased with increasing the sheet size. Further, the quantum mechanics calculation was used to investigate the adsorption property of the Ag atom adsorbed to the nanosheet graphene (expressed by C90H30) surface. The calculations show that the Ag atom binds to the bridge site (B site) of triangular nanosheet graphene (C90H30) as it is the most stable adsorption site compared with others, and since it has higher formation energy (Delta E) with shorter distance between the Ag atom and the graphene surface. Above all, calculations suggest that the Ag-adsorbed nanosheet graphene is a good option as an adsorbent in environmental research.