Ab initio investigation of Al- and Ga-doped single-walled boron nitride nanotubes as ammonia sensor

We performed first-principles calculations on the ammonia (NH3) adsorption properties with zigzag and armchair single-walled BN nanotubes (SWBNNTs) using B3LYP/6-31G* basis set implemented in Gaussian 98 program. We considered the ammonia adsorption on structural and electronic properties of Al- and Ga-doped (8, 0), (5, 5) BNNTs. The adsorption energy for the most stable configuration of NH3 on Al-doped (8, 0) BNNT is about −0.182 eV, which is typical for the chemisorptions. We determined that both aluminum and gallium doping can significantly enhance the adsorption energy of NH3/BNNTs complexes. Our electronic results reveal that there is a significant orbital hybridization between two species in adsorption process being an evidence of covalent interaction.

► The electronic properties of NH3 on Al- and Ga-doped (8, 0) and (5, 5) BNNT are studied. ► The adsorption energy for NH3 on Al-doped (8, 0) BNNT is higher than that of Ga-doped (8, 0) BNNT. ► The relation between adsorption energy and charge transfer was investigated.