A density functional theory study of molecular H2S adsorption on (4,0) SWCNT doped with Ge, Ga and B

The molecular adsorption of hydrogen sulfide has been investigated theoretically by using Density Functional Theory for gallium (Ga), germanium (Ge) and boron (B) doped (4,0) single-walled carbon nanotubes (SWCNTs). The method of B3LYP was utilized with basis sets of 6-31G(d,p) and LANL2DZ. Adsorption energy and adsorption enthalpy, HOMO and LUMO energy values, HOMO-LUMO energy gap, chemical hardness, chemical potential, electronegativity and Gibbs free energy values have been evaluated in this study. All doped SWCNT structures have negative Gibbs free energy and adsorption energy values which make these clusters promising for the removal of H2S by adsorption. However, Ge doped SWCNT cluster has the lowest HOMO-LUMO energy gap and chemical potential, highest electronegativity with minimum adsorption energy values when compared to other clusters. Furthermore, it is softer than other metal doped SWCNT clusters due to the lower chemical hardness value.