Adsorption and sensing performance of graphenylene nanosheet toward chlorofluorocarbons; a theoretical study

The adsorption and detection of chlorofluorocarbons (CFCs) using diverse 2D sensing materials is of significant environmental concern due to their toxic and long-term persistence in the atmosphere. This work employs density functional theory to assess the sensing potential of a graphenylene surface toward selected CFC molecules viz. CFC11 (trichlorofluoromethane, CCl₃F), CFC12 (dichlorodifluoromethane, CCl₂F₂), and CFC13 (chlorotrifluoromethane, CClF₃) in the gas phase. Optimized geometrical parameters and adsorption energy calculations indicate minimal structural perturbation of the GPNL surface, with negative E _ads values demonstrating energetically favorable interactions observed for all CFC@GPNL complexes. The calculated adsorption energies indicate favorable interactions between the analytes and the graphenylene nanosheet, following the order CFC-11@GPNL (-0.37 eV) > CFC-12@GPNL (-0.32 eV) > CFC-13@GPNL (-0.27 eV), suggesting physisorption for all investigated systems. The HOMO-LUMO energy gap analysis revealed a decrease in energy gap after adsorption, showing enhanced electrical conductivity, with CFC-11@GPNL complex identified as the most chemically reactive species among the other complexes. To ascertain the physisorption interaction of CFC molecules on the graphenylene surface, PDOS, and NBO analyses were performed. Electrostatic potential maps were employed to locate and characterize the adsorption sites and surface reactivity across the molecular surface. Furthermore, complementary QTAIM and NCI analyses confirmed the predominance of weak van der Waals (vdW) interactions, as evidenced by green regions in the 3D isosurfaces along with green scatter points appearing in the RDG graph. Among the investigated analytes, CFC-11 and CFC-12 demonstrate higher sensitivity and faster recovery times, demonstrating the promise of graphenylene as a viable sensing material for CFC detection.