Investigation of sensing behavior of carbon nitride (C6N8) for detection of phosphine (PH3) and phosphorous trichloride (PCl3): A DFT approach

This study shows the exploration of the gas-sensing capabilities of C₆N₈ material against toxic gases like phosphine (PH₃) and phosphorous trichloride (PCl₃). First-principles study based on M05-2X/LanL2DZ (d, p) method was performed to investigate the interaction energy (E_int.), frontier molecular orbitals (FMOs), natural bonding orbital (NBO), noncovalent interactions (NCIs), partial density of states (PDOS), molecular electrostatic potential (MEP), and quantum theory of atoms in molecules (QTAIM) analyses. The interaction energy results showed that PCl₃@C₆N₈ (−23.45 kJ/mol) is more stable than PH₃@C₆N₈ (−14.79 kJ/mol). A considerable decrease in the HOMO-LUMO band gap of C₆N₈ was observed as a result of its complexation with the analytes. QTAIM and NCI analyses indicated the presence of weak noncovalent interactions between C₆N₈ and gases (PH₃ and PCl₃). SAPT0 analysis was performed to quantify the NCIs. MEP maps of complexes revealed the localization of electronic density on C₆N₈. The little recovery time of complexes (determined at 300 K) showed that C₆N₈ can serve as a reusable sensing material against PH₃ and PCl₃. Our results demonstrate that the C₆N₈ surface is a reliable material for detecting phosphine and phosphorous trichloride gases.