To explore the potential application of boron nitride nanotubes (BNNTs) in chemical sensor devices, we investigate the adsorption properties of the pristine and silicon doped (Si-doped) (8, 0) single-walled BNNTs towards the toxic gas cyanogen chloride (ClCN) molecule by performing density functional theory (DFT) calculations. The results show that the Si-doped BNNT presents strong chemisorption to the ClCN molecule at both the silicon-substituted boron defect site and the silicon-substituted nitrogen defect site, which is in contrast with the weak physisorption on the pristine BNNT. The calculated electronic density of states (DOSs) further indicate that the doping of the Si atom results in the remarkable changes of the electronic structure of the BNNT near Fermi level, and the introduction of the local states decreases the band gap and increases the adsorption sensitivity towards the toxic ClCN molecule. The Si-doped BNNT is expected to be a potential resource for detecting the presence of toxic ClCN.

Key words: boron nitride nanotube, silicon, doping, cyanogen chloride, density functional theory