Silicon Carbide and Its Germanium Dopant Nanocluster Derivatives as Sensors for Chloropicrin: Perception from Density Functional Theory and Monte-Carlo MD Simulation

Pivotal to this research is the computational investigation of the nanosensing resourcefulness of silicon carbide, Si12C12 nanocage for the adsorption and detection of chloropicrin (CP). To fill this research gap, pristine Si12C12 was functionalized with Ge and the interaction configuration was modified into four adsorbent-adsorbate systems: using CP and the pristine Si12C12 at the Si and C sites respectively with GeSi12C11 and GeSi11C12 serving as complementary adsorbents for the third and fourth interactions. The electronic properties, thermodynamics, density-of-state and topology were investigated in addition to the adsorption energies all at the ωB97XD/aug-cc-pVDZ levels of theory. Also, the Cohesive Energy Density (CED), and MD simulation were carried out to investigate the stability of the nanocages and their respective interactions. The energy gap (Egp) varied from 5.127 to 6.220 eV with CP@C_Si12C12 and CP@GeSi12C11 at the lower and upper extremes while the ∆H, ∆G and S, which were all spontaneous and favourable had value ranges of −66.322 to −74.932 eV, −66.797 to −75.424 eV and 175.202 to 188.331 Cal/molK−1 respectively. The magnitude of the adsorption energy for the interactions showed strong chemisorption with the two lowest values of −67.025 and −67.231 eV corresponding to CP@Si_Si12C12 and CP@C_Si12C12 respectively. Furthermore, the non-covalent interaction (NCI) investigation complemented by the quantum theory of atoms in molecules (QTAIM) analysis showed that van der Waals forces were formed at CP-sensor interphase of CP@C_Si12C12 while varying degrees of steric hindrances were equally observed in addition to the van der Waals forces in the other three. From the sensor mechanism investigation, the most feasible recovery time of 5.98 × 1029s and 4.38 × 1029s was predicted for CP@C_Si12C12 and CP@Si_Si12C12 respectively.