Adsorption of molecular oxygen on the walls of pristine and carbon-doped (5,5) boron nitride nanotubes: Spin-polarized density functional study

Jia Zhang, Kian Ping Loh, Jianwei Zheng, Michael B. Sullivan and Ping Wu

Phys. Rev. B, 2007, 75, 245301.

Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Institute of High Performance Computing, Capricorn, Singapore Science Park II, Singapore 117528

Received 15 December 2006; revised 14 February 2007; published 5 June 2007

ABSTRACT:

We performed ab initio calculations to study the effect of molecular oxygen adsorption on the electronic properties of (5,5) pristine and carbon-doped boron nitride (BN) nanotube. The binding energies of oxygen molecules physisorbed at different sites were determined by considering both short- and long-range interactions. Spin-polarized calculation within the density functional theory yielded the triplet ground state for oxygen physisorbed on pure BN nanotube; the large energy gap between the unoccupied oxygen levels and the top of the valence band indicates the absence of hole doping. The introduction of substitutional carbon impurity increases the reactivity of BN nanotube toward molecular oxygen and stable O₂ chemisorption states exist on both carbon-substituted nitrogen site (C_N) and carbon-substituted boron site (C_B) defect sites. Chemisorbed O₂ on the CN defect is found to impart metallicity on the BN nanotube.

DOI: 10.1103/PhysRevB.75.245301