Interaction of CO, CO2, CSO, H2O, N2O, NO, NO2, O2, ONH, and SO2 gases onto BNNT(m,n)_x, (m = 3, 5, 7; n = 0, 3, 5, 7; x = 3–9)

Abstract

Context

This research investigates two critical areas, providing valuable insights into the properties and interactions of boron nitride nanotubes (BNNTs). Initially, a variety of BNNT structures (BNNT(m,n)_x, where m = 3, 5, 7; n = 0, 3, 5, 7; x = 3–9) with different lengths and diameters are explored to understand their electronic properties. The study then examines the interactions between these nanotubes and several gases (CO, CO₂, CSO, H₂O, N₂O, NO, NO₂, O₂, ONH, and SO₂) to identify the most stable molecular configurations using the bee colony algorithm for global optimization. The primary findings highlight the impact of nanotube diameter on these properties. It was observed that smaller diameters result in a larger energy gap due to increased quantum confinement. Significant charge transfer, especially with CO, was detected, affecting the electronic structure of the nanotubes. The study highlighted that BNNTs exhibit the strongest adsorption tendencies for NO₂, O₂, and SO₂. These findings underscore the critical roles of nanotube diameter and charge transfer in sensor applications and demonstrate the comprehensive utility of various analytical methods in understanding BNNT-gas interaction mechanisms.

Methods

The research employs a comprehensive computational framework based on density functional theory (DFT). Various DFT methods, such as PBE0, B3LYP(GD3BJ), CAM-B3LYP, HSE06i, M06-2X, and ωB97XD functionals, are utilized along with the Def2tzvp basis set for the calculations. Structural optimizations are performed to ensure accuracy, and modifications to the energy gaps are analyzed using conceptual DFT. Additionally, Total Density of States (TDOS) analyses are conducted. Charge transfer mechanisms are investigated through Natural Bond Orbital (NBO) analysis. The interactions between gases and nanotubes are characterized at critical points using the Quantum Theory of Atoms in Molecules (QTAIM) framework.