The Studies Of The Adsorption Mechanism Of Acetone And Flavonol On Boron Nitride Nanotubes By Density Functional Theory

With the development of nanotechnology,nanomaterials have been widely studied and applied in various fields.Compared with carbon nanotubes(CNT),boron nitride nanotubes(BNNT)have similar structures.The boron nitride nanotubes have unique properties due to the ionic properties of B-N bond in the nanotubes.Meanwhile,the structure of boron nitride nanotubes can be optimized,doped and filled to further change the nature of boron nitride nanotube,so as to show better properties in electricity,mechanics and adsorption.In this paper,the doping and adsorption mechanism of boron nitride nanotubes were investigated by theoretical calculation.This paper is divided into two parts:(1)The sensor properties of single-walled boron nitride nanotubes towards acetone are studied by investigating the intermolecular interactions of acetone with a serials of pristine and doped boron nitride nanotube.Density-functional theory(DFT)with empirical dispersion corrected is adopted to explore the adsorption properties of acetone on the surface of boron nitride nanotube.Results show that acetone binds strong to the surface of pristine boron nitride nanotubes with small diameter and the adsorption energy decreases significantly as the tube diameter increases.The adsorption of acetone on serials of doped boron nitride nanotube(Al,Si,Cu,Co,Ni,Ga,and Ge)shows that the adsorption of acetone on boron nitride nanotube can be strengthened by the doped impurity.With the analysis of charge density,density of states,molecular orbitals,and the noncovalent interaction index(NCI),the study shows that the sensitivity of BNNTbased chemical gas sensor towards acetone can be remarkable improved by introducing appropriate dopant.(2)The optical and electronic properties of four representative flavonols,both on the surface and confined in the single-walled boron nitride nanotubes,have been explored comparatively by self-consistent density-functional based tight-binding method(SCC-DFTB)and density-functional theory(DFT).The weak interactions are explicitly described by dispersion correction in the density-functional methods.The intermolecular interactions between flavonols and the boron nitride nanotube are investigated by analyzing the optimized structure and binding energies.The results show that the flavonols inside the boron nitride nanotube have a larger adsorption energy.The influence of mutual interaction between flavonols and boron nitride nanotube on the excited properties and UV/Vis of the complex structure are studied by time-dependent density functional theory.Due to the interaction of flavonols with boron nitride nanotube and the weakness of the intramolecular hydrogen,our results indicate a red-shift of the flavonol spectra when they are outside or inside the tube.With the analysis of reduced charge density,density of states,and molecular orbitals,the study concludes that the properties of flavonols can be fine-tuned by the interaction with boron nitride nanotube.