A Computational Study of Organosulfur Adsorption on Silicon Fullerenes: Implications for Improving Environmental Safety

This study investigates the adsorption of dibenzothiophene (DBT) on newly tailored silicon-based fullerene materials for environmental remediation and sensing applications. DBT is a polycyclic aromatic hydrocarbon (PAH) containing sulfur, which is a common impurity present in fossil fuels, automobile emissions, natural resources, and industrial discharges. It contributes to atmospheric acidity, a pioneer of acid rain. Its high toxicity causes lung diseases that affects humans and aquatic animals. The need for its detection and removal is critical to remediating these challenges. This study employs the density functional theory (DFT) approach at the PBE0-D3/LanL2DZ computational method to evaluate the interaction of DBT on newly tailored silicon-based fullerene materials doped with Cu, Ir, and Pt (DBT-Si₅₉Cu, DBT-Si₅₉Ir, and DBT-Si₅₉Pt). The adsorption energies observed ranged from -1.966 to -1.323 eV, indicating strong chemisorption of DBT on all modified silicon-based fullerenes. Si₅₉Ir showed the strongest adsorption (-1.966 eV), followed by Si₅₉Pt (-1.415 eV) and Si₅₉Cu (-1.323 eV). Electronic structure analysis revealed significant charge transfer and increment in dipole moment upon DBT adsorption, with values of 10.415, 10.130, and 8.342 D for DBT-Si₅₉Ir, DBT-Si₅₉Pt, and DBT-Si₅₉Cu, respectively. The HOMO–LUMO energy gaps decreased after adsorption from 0.317, 0.541and 0.461 eV in Si₅₉Cu, Si₅₉Ir, and Si₅₉Pt to 0.028, 0.049, and 0.163 eV in DBT-Si₅₉Cu, DBT-Si₅₉Ir, and DBT-Si₅₉Pt, respectively. This indicates enhanced reactivity. Our findings highlight the effectiveness of transition metal-doped silicon-based fullerenes in enhancing the efficiency of DBT capture. The strong adsorption characteristics and electronic properties of these materials suggest their potential as efficient adsorbents for DBT removal in environmental applications. This study introduces a novel application of silicon-based fullerenes for DBT adsorption, providing insights into their potential for future nanomaterial-based desulfurization strategies.