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.