A path for synthesis of boron-nitride nanostructures in volume of arc plasma

Abstract

We find a possible channel for direct nanosynthesis of boron-nitride (BN) nanostructures, including growth of BN nanotubes from a mixture of BN diatomic molecules by quantum-classical molecular dynamics simulations. No catalyst or boron nanoparticle is needed for this synthesis, however the conditions for the synthesis of each of the nanostructures, such as temperature and flux of the BN feedstock are identified and are compatible with the conditions in an electric arc at high pressure. We also find that BN nanostructures can be synthetized by feeding a boron nanoparticle by BN diatomic molecules, however if hydrogen rich molecules like NH or HBNH are used as a feedstock, two-dimensional nanoflake stable structures are formed.

Simulations of the synthesis of boron-nitride nanostructures in a hot, high pressure gas volume

“…One may argue that the label Born–Oppenheimer MD (BOMD) better conveys that nuclei are treated classically while the electrons are treated quantum-mechanically. indicate that highly organized BNNS such as BN cages and BNNTs can self-assemble simply from BN or BN-containing molecules without the presence of a pre-existing catalyst nanoparticle, 24 as well as by exposure of boron clusters to a nitrogen atmosphere. 24 – 26 In both cases, high temperature conditions of around 2000 K are shown to be crucial in the process, enabling fast diffusion of N, B or BN species to an adequate lowest energy position in the nanolattice, usually towards structural defects and the open or closed ends of the tubes.…”

“…indicate that highly organized BNNS such as BN cages and BNNTs can self-assemble simply from BN or BN-containing molecules without the presence of a pre-existing catalyst nanoparticle, 24 as well as by exposure of boron clusters to a nitrogen atmosphere. 24 – 26 In both cases, high temperature conditions of around 2000 K are shown to be crucial in the process, enabling fast diffusion of N, B or BN species to an adequate lowest energy position in the nanolattice, usually towards structural defects and the open or closed ends of the tubes. We further reported that the presence of hydrogen in the plasma could also play a decisive role by driving the change of sp-hybridization of B and N atoms from trivalent sp 2 to tetravalent sp 3 , 25 in agreement with experimental observation.…”

“…The main objective of this work is to investigate the roles of the precursor content, temperature and time for clustering and agglomeration of nanoparticles, in an atmosphere of boron, nitrogen, and where applicable, hydrogen atoms and/or small chemical compounds, within a temperature range from 1500 to 6000 K. This simulation design differs from our previous studies where nanoparticles were already present from the start of the simulations. 24 , 25 Due to the use of the NVT canonical ensemble in our simulations, the pressure changes with temperature, and it also changes with time, since the particles associate and agglomerate, changing the number of particles n which determines translational kinetic energy. As in our previous publications, 24 , 25 we used QCMD since we noted that our application of the classical molecular dynamics was not effective in producing ordered BN structures, resulting in mainly amorphous nanostructures.…”

Synthesis of boron nitride nanotubes using an oxygen and carbon dual-free precursor

“…7 Therefore, BNNTs show great promise in numerous potential elds such as optical systems, 8 electrical nano-devices, 9 energy storage, 10 nuclear reactor facilities, 11 radiation shielding in space vehicles, 11 and biomedical areas. [12][13][14] To date, various fabrication techniques, including chemical vapor deposition (CVD), 15,16 ball milling, 17,18 laser ablation, 19 plasma jet, 20,21 arc discharge, 22 and boron ink painting, 23,24 have been adopted for BNNT growth. However, there are several problems, such as very high fabrication temperatures (1100-2700 C), dangerous chemicals, non-uniform size and diameter, amorphous structure, small aspect ratios, and most importantly, undesirable impurities in gas grown products, associated with these techniques.…”

Molecular dynamics simulations for hydrogen adsorption in low energy collisions with carbon and boron-nitride nanotubes

“…Therefore, the electronic energies are computed as a sum over the occupied single-particle and diatomic repulsive energy contributions. Here, we utilize the SKF pair potentials set for materials science simulations (MATSCI-03) 26 , as implemented in the DFTB+ code, version 1.2 28 , which shows a good agreement with potential energy curves obtained from more elaborated DFT calculations [29][30][31][32] . This demonstrates that the SCC-DFTB results have an accuracy close to those obtained by DFT, but with a smaller computational cost.…”