Nanostructured gas sensors find diverse applications in environmental and agricultural monitoring. Herein, adsorption of phosgene (COCl₂) on pure and copper-decorated B₁₂N₁₂ (Cu–BN) is analyzed through density functional theory (DFT) calculations. Adsorption of copper on B₁₂N₁₂ results in two optimized geometries, named [email protected]₆₆ and [email protected]₆₄, with adsorption energies of −193.81 and −198.45 kJ/mol, respectively. The adsorption/interaction energies of COCl₂ on pure BN nanocages are −9.30, −6.90, and −3.70 kJ/mol in G1, G2, and G3 geometries, respectively, whereas the interaction energies of COCl₂ on copper-decorated BN are −1.66 and −16.95 kJ/mol for B1 and B2, respectively. To examine the changes in the properties of pure and Cu–BN nanocages, geometric parameters, dipole moment, Q_NBO, frontier molecular orbitals, and partial density of states (PDOS) are analyzed to comprehensively illustrate the interaction mechanism. The results of these parameters reveal that COCl₂ binds more strongly onto copper-doped BN nanocages. Moreover, a higher charge separation is observed in COCl₂–Cu–BN geometries as compared to copper-decorated BN geometries. Therefore, these nanocages may be considered as potential candidates for application in phosgene sensors.

Density functional theory calculations have been performed for alkali metal encapsulated X₁₂Y₁₂ nano-cages (X = B, Al and Y = N, P) to evaluate their stability, boundary crossing barriers and optical (linear and non-linear) properties.