The CN surface as a highly selective sensor for the detection of nitrogen iodide from a mixture of NX (X = Cl, Br, I) explosives.

Explosives are quite toxic and destructive; therefore, it is necessary to not only detect them but also remove them. The adsorption behavior of NX analytes (NCl, NBr and NI) over the microporous CN surface was evaluated by DFT calculations. The nature of interactions between NX and CN was characterized by adsorption energy, NCI, QTAIM, SAPT0, NBO, EDD and FMO analysis. The interaction energies of NX with CN are in the range of -10.85 to -16.31 kcal mol and follow the order of NCl@CN > NBr@CN > NI@CN, respectively. The 3D isosurfaces and 2D-RGD graph of NCI analysis qualitatively confirmed the existence of halogen bonding interactions among the studied systems. Halogen bonding was quantified by SAPT0 component energy analysis. The SAPT0 results revealed that Δ (56.75%) is the dominant contributor towards interaction energy, whereas contributions from Δ and Δ are 29.41% and 14.34%, respectively. The QTAIM analysis also confirmed the presence of halogen bonding between atoms of NX and CN surface. EDD analysis also validated NCI, QTAIM and NBO analysis. FMO analysis revealed that the adsorption of NI on the CN surface caused the highest change in the gap (from 5.71 to 4.15 eV), and resulted in high sensitivity and selectivity of the CN surface towards NI, as compared to other analytes. It is worth mentioning that in all complexes, a significant difference in the gap was seen when electronic transitions occurred from the analyte to the CN surface.