Chloropicrin sensor based on the pristine BN nanocones: DFT studies

We investigated the chloropicrin adsorption on the BN nanocones using DFT calculations. We selected two kinds of BN nanocones with 180 disclination angle entailing BN-N (including N-N bonds) and BN-B (including N-N bonds). The chloropicrin strongly interacts with B-B bonds of the BN-B nanocone so that the adsorption energy is about − 135.3 kcal/mol. By going away from the apex, the reactivity of B-B bonds is decreased. The electronic properties of BN-B nanocone are not affected, and also, its recovery is impossible because of a cycloaddition process. Thus, it cannot be used in the chloropicrin sensors. In contrary, the BN-N nanocone adsorbs the chloropicrin with adsorption energy about − 11.0 kcal/mol. However, the reactivity of the BN-N is considerably lower than the BN-B. By the adsorption of the chloropicrin, the LUMO level of BN-N nanocone significantly stabilized so that the HOMO-LUMO gap is decreased by about 84.1%. Consequently, the BN-nanocone converts from a semiconductor to a semimetal with a higher electrical conductivity. The change of electrical conductivity can create an electrical signal which helps to detect the chloropicrin. We predicted a short recovery time of 3.7 × 10−5 s at 298 K for this sensor.