Investigation of phosgene adsorption behavior on aluminum nitride nanocones: Density functional study

The adsorption of phosgene molecule on two kinds of AlN nanocones (AlN-Al and AlN-N) was investigated based on the density functional theory calculations. It was found that the phosgene is dissociated on the AlN-Al nanocone with adsorption energy about − 98.3 kcal/mol, and a CO molecule is released. Although the electrical conductivity of the AlN-Al increases by the phosgene adsorption, it cannot be used as a sensor because of desorption difficulty. In contrary, the AlN-N nanocone adsorbs the phosgene gas releasing an energy about − 22.1 kcal/mol, indicating that the reactivity of the AlN-N nanocone is considerably lower than that of the AlN-Al one. Thus, the AlN-N nanocone benefits from a short recovery time about 51 ms at room temperature. After the phosgene adsorption, the lowest unoccupied molecular orbital of AlN-N nanocone significantly stabilizes so that the Eg decreases from 2.32 to 0.59 eV. Therefore, the AlN-N nanocone converts from a semiconductor to a semimetal, increasing the electrical conductivity. The change of electrical conductivity can create an electrical signal which helps to detect the phosgene gas.