DFT study of the adsorption of simple organic sulfur gases on g-C3N4; periodic and non-periodic approaches

Abstract

In the present work, the adsorption of some simple organic sulfur gases (CS2, OCS, and CH3SH) on the g-C3N4 was studied using periodic and non-periodic density functional theory (DFT). PBE-D3/DNP and B3LYP-D3/6-31G(d) levels of theory were employed for periodic and non-periodic calculations, respectively. The calculated CS2, OCS, and CH3SH adsorption energies were obtained to be −4.35, −5.82, and −8.58 Kcal/mol. The interactions of simple organic sulfur gases with g-C3N4 were characterized by NBO second-order perturbation theory and quantum theory of atom in molecule (QTAIM). The bandgap energies and work function of g-C3N4 and its complexes with simple organic sulfur gases were extracted from their band structures. The CS2 and OCS adsorptions didn’t significantly alter the bandgap and work function of g-C3N4. Therefore, g-C3N4 is not a proper sensor for detecting CS2 and OCS. The bandgap and work function of g-C3N4 were averagely changed by 18% and 2.7%, respectively, after CH3SH adsorption. Accordingly, g-C3N4 may use as a suitable sensor for detecting CH3SH based on electronic conductivity and work function.