Molecular modelling of Al24N24 nanocage for the chemical sensing of phosgene and mustard chemical warfare agents: First theoretical framework

Abstract

This research uses the efficiency of nanostructured Al24N24 for the rapid detection and sensing of phosgene and mustard chemical warfare agents (CWA). Frontier molecular orbitals (FMO), natural bond orbitals (NBO), density of states (DOS), topological analysis like non-covalent interactions (NCI) and quantum theory of atoms in molecules (QTAIM), sensing mechanism, and recovery time analysis were used to assess the adsorbing capabilities of the investigated Al24N24-nanocage. Mustard gas adsorption energy was strongest, ranging between −25.064 to –22.928 Kcal. Phosgene complexes had lower adsorption energies than mustard complexes ranging from −12.818 to −5.422 Kcal. The Frontier molecular orbitals (FMO) study demonstrates that phosgene and mustard gas adsorption on Al24N24 nanocage reduces the energy gap. Adsorption of phosgene results in the lowest energy gap of 2.91 eV (-29 %) for three complexes, namely P-Cl@4m, PO@6m, and P-planer@4m; hence, a much better sensing response 2.77 × 10−1 and a quicker recovery time of 3.93 × 10−10sec. These complexes have high softness (0.344 eV), low hardness (1.455 eV) and chemical potential of (-4.721 eV), which indicate high reactivity and low stability. Consequently, the Al24N24 nanocage is recommended as a fine future sensor for sensing phosgene and mustard CWA, with a much better response for phosgene.