Title: Boron nitride nanotube precursor formation during high-temperature synthesis: kinetic and thermodynamic modelling

Abstract

In this work, we performed integrated modelling of the chemical pathways of formation for boron nitride nanotube (BNNT) precursors during high-temperature synthesis in a B/N₂ mixture. Integrated modelling includes quantum chemistry, Quantum–classical molecular dynamics, thermodynamic modelling, and kinetic approaches. We demonstrate that BN compounds are formed via the interaction of molecular nitrogen with small boron clusters, rather than through interactions with less reactive liquid boron. (This process can also be described as N₂ molecule fixation.) Liquid boron evaporates to produce these boron clusters (B_m with m ≤ 5), which are subsequently converted into B_mN_n chains. The production of such chains is crucial to the growth of BNNTs because these chains form the building blocks of bigger and longer BN chains and rings, which are in turn the building blocks of fullborenes and BNNTs. Additionally, kinetic modelling revealed that B₄N₄ and B₅N₄ species in particular play a major role in the N₂ molecule fixation process. Furthermore, the formation of these species via reactions with B₄ and B₅ clusters is not adequately described under the assumption of thermodynamic equilibrium, as is demonstrated in our kinetic modelling. Thus, the accumulation of both B₄N₄ and B₅N₄ depends on the background gas pressure and themore » gas cooling rate. Long BN chains and rings, which are precursors of the fullborene and BNNT growth, form via self-assembly of components B₄N₄ and B₅N₄. Our modelling results—particularly the increased densities of B₄N₄ and B₅N₄ species at higher gas pressures—explain the experimentally observed effect of gas pressure on the yield of high-quality BNNTs. The catalytic role of hydrogen was also studied; it is shown that HBNH molecules can be the main precursor of BNNT synthesis in the presence of hydrogen.« less

Authors:

Barsukov, Yuri  ^[1];

• Search DOE PAGES for author "Barsukov, Yuri"
• Search DOE PAGES for ORCID "0000-0002-3487-5046"

Dwivedi, Omesh  ^[2];

• Search DOE PAGES for author "Dwivedi, Omesh"
• Search DOE PAGES for ORCID "0000-0003-3633-8874"

Kaganovich, Igor  ^[2];

• Search DOE PAGES for author "Kaganovich, Igor"
• Search DOE PAGES for ORCID "0000-0003-0653-5682"

Jubin, Sierra ^[2]; Khrabry, Alexander ^[2]; Ethier, Stephane ^[2]

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+ Show Author Affiliations

1. Peter the Great Saint-Petersburg Polytechnic Univ. (Russia)
2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:

Tue Aug 31 00:00:00 EDT 2021

Research Org.:

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:

1822273

Grant/Contract Number:  

AC02-09CH11466

Resource Type:

Accepted Manuscript

Journal Name:

Nanotechnology

Additional Journal Information:

Journal Volume: 32; Journal Issue: 47; Journal ID: ISSN 0957-4484

Publisher:

IOP Publishing

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; boron clusters; boron nitride; DFT; chains; fullborenes; kinetics; MCSCF; molecular dynamic; nanotubes; nitrogen fixation; precursor; rings; thermodynamic.