Adsorption properties of nitrogen dioxide on hybrid carbon and boron-nitride nanotubes

Abstract

The properties of pristine carbon nanotubes (CNTs) can be modified in a number of different ways: covalent attachments, substitutional doping, induced defects, and non-covalent interactions with ligands. One unconventional approach is to combine CNTs with boron-nitride nanotubes (BNNTs) to form hybrid carbon and boron-nitride nanotube (CBNNT) materials. In this work, we perform a first-principles density functional theory study on the adsorption properties of NO₂ on CBNNT heterostructures. It is found that the adsorption of NO₂ is significantly increased on both zigzag CBNNT(8,0) and armchair CBNNT(6,6), as compared to either a pristine CNT or BNNT. For example, the chemisorption of NO₂ on CNT(8,0) is found to be endothermic, while the chemisorption of NO₂ on CBNNT(8,0) is an exothermic process with a very large binding energy of −27.74 kcal mol⁻¹. Furthermore, the binding of NO₂ on both CBNNT(8,0) and CBNNT(6,6) induces an increase in the conductivity of the nanotube. These characteristics indicate that the CBNNT heterostructures may have significant potential as an NO₂ sensor or as a catalyst for NO₂ decomposition reactions. Our calculations provide critical information for further evaluation, such as molecular-level adsorption simulations and microkinetic studies.