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.