Adsorption and sensor applications of C2N surface for G-series and mustard series chemical warfare agents

Adsorption of toxic chemical warfare agents (tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), N-mustard (NM), S-mustard (SM) on carbon nitride (C2N) surface is explored by employing density functional theory and molecular dynamics simulations. Interaction energy, SAPT0, NCI and QTAIM analyses reveal that all CWAs are weakly physiosorbed over C2N surface. The stability of the complexes results due to dispersion interactions (hydrophobic nature) between interacting atoms of CWAs with C2N surface. Electronic properties of CWAs@C2N complexes are studied through NBO, EDD, and FMO analyses. Adsorption of GA, GD, NM and SM over C2N surface causes transfer of charge towards C2N, whereas, GB and GF extract charges from C2N. The highest interaction energy (−18.66 kcal/mol) is observed for GF@C2N complex the FMO analysis and MD simulations reveal that C2N surface is more selective towards NM. FMO analysis reveals that adsorption of NM on C2N surface not only causes significant decrease in EH-L gap but the distribution of density is shifted from analyte to C2N upon excitation from HOMO to LUMO. Recovery time of 1.36 s for desorption of NM from C2N surface shows that C2N can act as promising surface as an electrochemical sensor for NM detection.