Investigation of adsorption properties of CS2 on interior and exterior surfaces of single-walled silicon-carbide nanotubes and effect of applied electric field: electronic structure, charge density and NMR studies†
Abstract
The adsorption behavior of the CS2 on the surface of silicon-carbide nanotubes (SiCNTs) is studied by density functional theory. For both the external and internal cases, different configurations of the adsorbed CS2 onto the nanotube surface are studied. The energetic, geometric, and electronic properties have been investigated using B3LYP density functional. According to the obtained results, the process of CS2 molecule adsorption on different sites of the outer wall of the nanotube is exothermic and configurations are stable, while the process of CS2 molecule adsorption on the internal surface of the SiCNT is endothermic. The adsorption energy values indicated that the CS2 molecule can be physically or chemically adsorbed on the external surface of the SiCNT while for internal case, it can be chemically adsorbed on the internal wall. NBO analysis indicated that the CS2 molecule can be adsorbed on the nanotube with a charge transfer from the CS2 molecule to the nanotube. 13C and 29Si chemical shielding tensors are computed using the GIAO method. NMR calculations reveal that 13C and 29Si chemical shielding is changed upon the CS2 adsorption. As well as, the effect of external electric fields (EFs) on the adsorption properties of the geometric structures, adsorption energies, and band gap has been considered.