A DFT study on the sensing behavior of a BC2N nanotube toward formaldehyde.

We investigated the viability of using a BC2N nanotube to detect formaldehyde (H2CO) molecule by means of B3LYP and M06 density functionals. The results indicate that the molecule is weakly adsorbed on the intrinsic BC2N nanotube releasing energy of 0.8 kcal mol(-1) (at B3LYP/6-31G(d)) without significant effect on the HOMO-LUMO energy gap and electrical conductivity of the tube. Thus, H2CO cannot be detected using this intrinsic nanotube. To overcome this problem, a carbon atom of the tube wall was substituted by a Si atom. It was demonstrated that the Si-doped tube cannot only strongly adsorb the H2CO molecule, but also may effectively detect its presence because of the increase in the electric conductivity of the tube.