DFT study on the chemical sensing properties of B24N24 nanocage toward formaldehyde

Abstract

It has been previously shown that the toxic formaldehyde gas (H2CO) cannot be detected by pristine BC2N, carbon, and BN nanotubes, BC3 nanosheet and graphene. Herein, density functional theory calculations were employed to investigate the electronic and structural behavior of a pristine B24N24 nanocluster toward H2CO molecules. It was found that [4,6] BN bonds of the nanocluster are the most favorable sites for the H2CO adsorption, compared to the [4,8], and [6,8] ones. When an H2CO molecule is adsorbed on a [4,6] BN bond, an energy of about 16.40kcal/mol is released and the HOMO-LUMO gap of the cluster is decreased from 6.45 to 2.98eV. Thus, the electrical conductivity of the cluster is significantly increased, indicating that it can produce an electronic noise at the presence of H2CO molecules. Increasing the number of adsorbed H2CO molecules, the electrical conductivity more increases. The recovery time for the H2CO from the surface of B24N24 is calculated to be very short (∼1.02s). Also, the UV–vis spectrum shows that the λmax of the B24N24 shows a large redshift upon the adsorption process and transfers from the UV to the visible region.