DFT study of SCN- adsorption effect on structural and electronic properties of Si12C12 fullerenes

Utilizing density functional theory (DFT) calculations, the adsorption characteristics and electronic structure of thiocyanate anion (SCN-) through nitrogen and sulfur heads upon the Si12C12 surface were investigated by the B3LYP functional and 6-31 + G** standard basis set. The results express that the covalent interaction of SCNthrough the nitrogen head (-3.08 eV) is stronger in comparison with the sulfur head of SCN- (-2.32 eV) to the fullerene surface. Additionally, the interaction of two SCN- through nitrogen head has weaker surface adsorption on the silicon-carbon (Si-C) atom (-1.27 eV) in comparison with the Si-Si atom (-2.78 eV) of Si12C12 fullerene. The influence of SCN- adsorption on the Si12C12 surface was characterized by the infrared (IR) absorption spectrum. A significant orbital hybridization between SCN- and Si12C12 fullerenes occurred during the adsorption process, according to the computed density of states (DOS). According to the analysis of binding energy, energy gap, and dipole moment, Si12C12 fullerene can be applied to SCN- removal applications. Based on the thermodynamic parameters, the negative Gibbs free energy (Delta G) and enthalpy change (Delta H) values confirmed that the SCN- adsorption by the nitrogen heads on the Si12C12 surface was spontaneous and exothermic.