Synthesis Of Boron Nitride Nanotubes Research Articles

Ti-B-O System for Catalyzing Boron Nitride Nanotube Growth.

Chemical vapor deposition (CVD) stands out as the most promising method for cost-effective production of high-quality boron nitride nanotubes (BNNTs). Catalysts play a crucial role in BNNT synthesis. This work delves into the impact of oxygen (O) on Ti-based catalysts during the CVD growth of BNNTs. In contrast to the B/TiB2 nanoparticles (NPs) and B/TiN NPs systems, the oxygen-containing precursor B/TiO2 NPs remarkably catalyzes the growth of high-quality and high-purity BNNTs across a wider range of synthesis parameters. Subsequent analyses reveal that TiBO3 acts as an active catalyst, facilitating BNNT growth in Ti-based catalyst systems. Moreover, the nanocomposite film synthesized from BNNTs and PVDF-HFP exhibits excellent mechanical properties and heat dissipation capabilities. Utilizing the nanocomposite film as a thermal interface material effectively enhances the heat dissipation for a 5 W light-emitting diode (LED) chip. Consequently, our research confirms the effectiveness of the Ti-B-O system in catalyzing BNNT growth.

Boron nitride nanotubes synthesis from ammonia borane by an inductively coupled plasma

Boron nitride nanotubes (BNNTs) have been studied extensively due to their unique properties. Hydrogen-assisted induction thermal plasma with hBN powder has been reported in the past to produce high-yield small-diameter BNNTs. However, removal of unprocessed hBN and other BN-based impurities has been a challenge. This study presents a new approach for BNNT synthesis using ammonia borane (AB) as the raw material while maintaining the high yield and similar nanotube diameter and number of walls. Our findings demonstrate that the use of AB results in enhanced synthesis of BNNTs with reduced B and BN impurities formation. The presence of H in the proximity of B following AB decomposition facilitated more efficient formation of BH-based precursors that also lowered the partial pressure of B and restricted its condensation and coagulation into large B particles, ultimately leading to an increased density of B seeds required for BNNTs nucleation. Both the increased formation of BNNT precursors and B seeds contributed to more efficient BNNTs formation. XRD analysis revealed that AB-BNNTs contained no hBN, less tBN, and more BNNTs compared to hBN-BNNTs. Additionally, TGA and OES measurements confirmed formation of less B and production of more BH species, respectively. Our results suggest that AB as a feedstock for BNNT synthesis in induction thermal plasma offers a promising alternative to hBN powder.

Thermal Conductivity of Carbon/Boron Nitride Heteronanotube and Boron Nitride Nanotube Buckypapers: Implications for Thermal Management Composites.

To date, there has been limited reporting on the fabrication and properties of macroscopic sheet assemblies (specifically buckypapers) composed of carbon/boron nitride core-shell heteronanotubes (MWCNT@BNNT) or boron nitride nanotubes (BNNTs). Herein we report the synthesis of MWCNT@BNNTs via a facile method involving Atmospheric Pressure Chemical Vapor Deposition (APCVD) and the safe h-BN precursor ammonia borane. These MWCNT@BNNTs were used as sacrificial templates for BNNT synthesis by thermal oxidation of the core carbon. Buckypaper fabrication was facilitated by facile sonication and filtration steps. To test the thermal conductivity properties of these new buckypapers, in the interest of thermal management applications, we have developed a novel technique of advanced scanning thermal microscopy (SThM) that we call piercing SThM (pSThM). Our measurements show a 14% increase in thermal conductivity of the MWCNT@BNNT buckypaper relative to a control multiwalled carbon nanotube (MWCNT) buckypaper. Meanwhile, our BNNT buckypaper exhibited approximately half the thermal conductivity of the MWCNT control, which we attribute to the turbostratic quality of our BNNTs. To the best of our knowledge, this work achieves the first thermal conductivity measurement of a MWCNT@BNNT buckypaper and of a BNNT buckypaper composed of BNNTs not synthesized by high energy techniques.

Boron Nitride Nanotubes (BNNTs) and BNNT Composites: A Review

Abstract This paper provides a summary of recent advances in boron nitride nanotubes (BNNTs) and their composites, including properties, purification, characterization techniques involved, failure modes, and modeling methods. After the discovery of carbon nanotubes, BNNTs were first theoretically predicted and successfully synthesized in 1995 by an arc-discharge method. Following that, other techniques for BNNT synthesis were discovered; however, growing highly purified BNNTs remains difficult. The research on the physical properties of BNNTs shows that they have a stable broadband gap, excellent mechanical strength, high thermal conductivity, and high oxidation resistance. These properties make them a perfect candidate for future nanocomposites for high-temperature applications. Interesting effects of BNNT addition with the resultant mechanical behavior and thermal conductivity in a matrix are observed when BNNTs are applied to form nanocomposites with polymer, metal, and ceramic matrices. Modeling and simulation methods of nanotube composites are highly advantageous in developing BNNT-based nanocomposites. Micromechanics, finite element analysis, and molecular dynamics are modeling techniques used to simulate nanotubes and are crucial for model- informed manufacturing and design. In summary, modeling, synthesis, purification, characterization, and properties of BNNT composites are all reviewed in this paper.

Synthesis of boron nitride nanotubes in thermal plasma with continuous injection of boron under atmospheric pressure

Synthesis of boron nitride nanotubes in thermal plasma with continuous injection of boron under atmospheric pressure

Highly efficient synthesis of boron nitride nanotubes by catalytic chemical vapor deposition of boron/nickel containing precursors

High-purity and high-yield boron nitride nanotubes with large aspect ratio were prepared by a facile two-step process, including the synthesis of boron/nickel containing precursors by precipitation reactions and subsequent thermally catalytic chemical vapor deposition reactions. The influence of catalyst content and annealing temperature on the phase composition and microstructure of the products were investigated. The results show that it is difficult to exert the catalytic effect of nickel-based catalyst at low temperatures (<1 400 °C). At appropriate temperatures (1 400–1 500 °C), highly crystalline boron nitride nanotubes with a length of more than 50 μm and a diameter of 50 nm are formed. The content of catalyst in the precursor mainly affects the morphology of the boron nitride product. If the content is too low, it is easy to form boron nitride particles; while high catalyst content can easily lead to catalyst aggregation and form a submicron one-dimensional boron nitride with unregular structure. Based on microstructural evolutions, phase changes, and thermodynamic analysis, the vapor-liquid-solid (V-L-S) growth mechanism of the tip growth mode dominates the formation of boron nitride nanotubes has also been verified.

Spontaneous formation of boron nitride nanotube fibers by boron impurity reduction in laser ablation of ammonia borane

Highly crystalline and few-walled boron nitride nanotubes (BNNTs) had been synthesized by laser ablation using only ammonia borane as a precursor. As a molecular precursor, ammonia borane supplied both B and N atoms with a ratio of 1:1, and BNNTs were formed via the homogeneous nucleation of BN radicals, not the growth from boron nano-droplets, which is a generally accepted growth mechanism of the laser-grown BNNTs. Owing to the absence of amorphous boron impurities, the van der Waals interaction among BNNTs became effective and thus a BNNT fibers was formed spontaneously during the BNNT synthesis. The BNNT growth and the subsequent fiber formation are found to occur only at high pressures of a surrounding gas. The mechanism behind the critical role of pressure was elucidated from the perspective of reaction kinetics and thermal fluid behaviors. A polarized Raman study confirmed that the BNNT fiber formed exhibits a good alignment of BNNTs, which implies great potential for continuous production of high-quality BNNT fibers for various applications.

Advances in synthesis and applications of boron nitride nanotubes: A review

• This review provides a comprehensive overview on BNNTs. • The synthesis, growth mechanism, applications of BNNTs are summarized. • The challenges in the synthesis of BNNTs by CVD method are also proposed. Boron nitride nanotubes (BNNTs) have attracted worldwide research interest since 1995 due to their excellent properties and a wide range of applications in numerous fields. The development of efficient preparation routes for BNNTs has always been the primary obstacle, limiting their practical application. In recent years, several exciting achievements have been realized in BNNTs synthesis. This paper briefly overviews some history of BNNTs development and updates the recent advances in the synthesis of BNNTs, more focusing on the CVD method from the perspectives of experiment devices, precursors, catalyst, and temperature as well as their growth mechanisms. We also summarized some advanced applications of BNNTs in composites, water purification membranes, biological applications, and optical devices. Future challenges and opportunities in the synthesis and applications of BNNTs are discussed as well.

Revealing the Effect of Sulfur Compounds for Low-Temperature Synthesis of Boron Nitride Nanotubes from Boron Minerals

Boron nitride nanotubes (BNNTs), the structural analogues to carbon nanotubes (CNTs), attracted considerable attention due to their excellent properties. However, the synthesis of BNNTs suffers from high-temperature requirement, which increases the cost and adds complexity to instruments (arc-discharge, plasma-assisted CVD, etc.), preventing further exploration of BNNTs and use of harmful chemicals (catalytic chemical vapor deposition) resulting in unwanted byproducts. Here, we demonstrate sulfur-containing compound-assisted synthesis of BNNTs at a relatively low temperature of 1050 °C from colemanite via a chemical vapor deposition (CVD) method. Comparison between thiophene, l-cystine, and l-methionine revealed that thiophene is the most effective sulfur compound with more stable decomposition products and low vapor pressure. Moreover, we have evaluated ulexite and etidot-67 as an alternative to colemanite. We believe that our findings can offer solutions to commonly encountered problems of BNNT synthesis in terms of high energy consumption and precursor cost, leading to broader use of BNNTs in various applications.

Synthesis of Boron Nitride Nanotubes Using Plasma-Assisted CVD Catalyzed by Cu Nanoparticles and Oxygen.

We found that oxidized Cu nanoparticles can catalyze the growth of boron nitride nanotubes from borazine via plasma-assisted chemical vapor deposition. The Raman spectra suggest that the formation of thin-walled nanotubes show a radial breathing mode vibration. The presence of oxygen in the plasma environment was necessary for the growth of the nanotubes, and a part of the nanotubes had a core shell structure with a cupper species inside it. In atomic resolution transmission electron microscope (TEM) images, Cu2O was found at the interface between the Cu-core and turbostratic BN-shell. The growth mechanism seemed different from that of carbon nanotube core-shell structures. Therefore, we pointed out the important role of the dynamic morphological change in the Cu2O-Cu system.

Single- and double-walled boron nitride nanotubes: Controlled synthesis and application for water purification

Research interest in boron nitride nanotubes (BNNTs) has increased after the recent success of large-scale BNNT syntheses using high-temperature-pressure laser ablation or high-temperature plasma methods. Nonetheless, there are limits to the application and commercialization of these materials because of the difficulties associated with their fine structural control. Herein, the growth kinetics of BNNTs were systemically studied for this purpose. The growth pressure of the nitrogen feed gas was varied while the growth temperature remained constant, which was confirmed by black body radiation measurements and calculations based on a heat loss model. Changing from the diffusion-limited regime to the supply-limited regime of growth kinetics based on the optimized BNNT synthesis condition afforded the control of the number of BNNT walls. The total amount of BNNTs possessing single and double walls was over 70%, and the BNNT surface area increased to 278.2 m2/g corresponding to small wall numbers and diameters. Taking advantage of the large surface area and high-temperature durability of the material, BNNTs utilized as a recyclable adsorbent for water purification. The efficiency of the BNNTs for capturing methylene blue particles in water was approximately 94%, even after three repetition cycles, showing the potential of the material for application in the filter industry.

Synthesis of boron nitride nanotubes using triple DC thermal plasma reactor with hydrogen injection

Highly crystalline boron nitride nanotubes (BNNTs) having multi-walls (≤5 walls) and a small diameter (~7 nm) were synthesized using a triple DC thermal plasma reactor with hydrogen injection. Triple torch configuration not only generates larger high temperature regions than single torch but also allow precursors to directly penetrate the core of the plasma flame, the hottest area in the reactor. A triple torch increases the productivity of BNNT synthesis by preventing the flow of precursors into the rim of plasma flame, a problem that occurs with single torch due to the high velocity and viscosity of the central flame. The role of hydrogen in the growth of BNNTs was analyzed by thermodynamic equilibrium reaction calculations and numerical analysis of thermal flow in the system. The reaction calculations revealed that hydrogen facilitates the formation of NH, NH2, and N2H2 molecules by inhibiting N from recombining into N2 in the high temperature region. Hydrogen influences the formation of scattered high temperature and enthalpy regions due to its thermal properties and expands the vortex region, leading to longer residence times for B-N-H intermediates in the reactive region. As a result, 12.6 g of BNNTs are produced with 21.4 kW of input power. A comparison with other methods shows that this yield is superior and provides an economic perspective for the proposed pilot synthesis of BNNTs.

Boron Nitride Nanotube Nucleation during Ni-Catalyzed Boron Oxide Chemical Vapor Deposition

Boron oxide chemical vapor deposition (BOCVD) has proved to be a valuable synthetic technique for the catalytic synthesis of boron nitride nanotubes (BNNTs) for almost two decades. However, the nuc...

Synthesis of Boron Nitride Nanotubes Incorporated with Pd and Pt Nanoparticles for Catalytic Oxidation of Carbon Monoxide

Facile synthesis of Pd and Pt nanoparticles supported on the boron nitride nanotubes (Pd-BNNT and Pt-BNNT, respectively) for CO oxidation was explored. The reduction agent and stabilizer-free synthesis solely relies on the ultrasound treatment of the aqueous Pd2+ and Pt4+ precursors under the presence of BNNT. Reduction of Pd and Pt nanoparticles on the surface of BNNT was observed by means of the transmission electron microscopy and X-ray diffraction patterns. Quantitative analysis of Pd and Pt attached on the BNNT surface was also carried out using inductively coupled plasma atomic emission spectroscopy, showing that the concentration of metal nanoparticles on BNNT could be controlled by varying the initial concentration of metal precursors and the ultrasound treatment time. The morphological evolution of the nanoparticles on the surface of BNNT was observed by raising the temperature up to 800 °C in an air and up to 900 °C in vacuum. It was found that the nanoparticles were thermally stable up to 600 °...

Novel and Facile Route for the Synthesis of Tunable Boron Nitride Nanotubes Combining Atomic Layer Deposition and Annealing Processes for Water Purification

AbstractThe synthesis of tunable boron nitride (BN) nanotubes is the subject of intense research because of their potential applications in various fields, from smart textile materials to emerging environmental technologies. However, the preparation of these nanomaterials remains extremely challenging. Herein, proof‐of‐concept results on the scalable synthesis of boron nitride nanotubes with tunable dimensions are reported. Combining atomic layer deposition (ALD) of boron nitride on carbon nanofibers template supports and successive annealing steps at high temperature, BN nanotubes with controllable properties are prepared. The successive annealing steps enable the crystallization of BN and the combustion of the initial carbon supports. The self‐limiting nature of the ALD process allows for the scalable coating of large scale carbon fibers matrix. High‐resolution transmission electron microscopy measurements demonstrate the exquisite dimensions control at the nanoscale and the presence of crystalline BN. The proof‐of‐concept results presented allow for independent control of the inner and external diameter dimensions, opening up unique possibilities for the precise engineering of BN nanotubes properties. The nanotubes present good mechanical properties, are easy to handle, and the assessment of their sorption properties shows that they absorb up to 110 times their own weight in oils while repelling water, which opens prospects for water purification.

Synthesis of boron nitride nanotubes by combining citrate-nitrate combustion reaction and catalytic chemical vapor deposition

High-quality boron nitride nanotubes were successfully synthesized via a novel two-step method, including citrate-nitrate combustion reaction and catalytic chemical vapor deposition. The composition, bonding features and microstructures of as-synthesized sample were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Raman microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, transmission electron microscopy and selected area electron diffraction techniques. The results show that the as-synthesized boron nitride nanotubes with smooth surface are relatively pure. The diameter ranges between 20 and 80 nm, while the length is about dozens of micrometers. During the synthesis process of boron nitride nanotubes, citric acid chelates the cobalt ions and reacts with nitrate to form the cobalt oxide, depositing on the surface of boron powder homogeneously. The catalyst content and annealing temperature have a significant impact on the composition and microstructures of the final products. Based on the experimental results and thermodynamic analysis, the possible chemical reactions are listed, and vapor-liquid-solid mechanism is proposed to be dominant for the formation of boron nitride nanotubes.

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

Synthesis of Boron Nitride Nanotubes and Boron Nitride Nanoflakes with Potential Application in Bioimaging

Hexagonal boron nitride (BN) is structural analogues to graphitic structure of carbon. Similar to graphene and carbon nanotubes, BN also has nanosheets structure, also known as white graphene and nanotubes structure. These BN nanostructures show excellent properties, such as high stability, mechanical strength and resistant to chemicals. Synthesis of BN nanosheets is easier as compared to synthesis of its 1D nanostructure due its hexagonal layered structure, in which stacks are attached with each other by weak Van der Waals forces. In the present work, synthesis and applications of 1D and 2D nanostructures are discussed. Growth of BN nanotubes on tungsten substrate was performed by using copper as catalyst with a simple and easy method. Synthesis of fluorescent BN nanoflakes was performed using solid precursor, boric oxide and urea for boron and nitrogen, in a high-temperature furnace under argon atmosphere. The product was ultrasonicated in water to get completely stable dispersion of fluorescent nanoflakes as final product. Both The product was then characterized by FESEM, TEM, FTIR. The fluorescence behaviour of BN nanoflakes was also measure and applied for bioimaging of breast cancer cells (MCF-7).

Catalytic synthesis of boron nitride nanotubes at low temperatures.

KFeO2 is demonstrated to be an efficient catalyst for the formation of boron nitride nanotubes (BNNT) by thermal chemical vapor deposition (TCVD). This alkali-based catalyst enables the formation of crystalline, multi-walled BNNTs with high aspect ratio at temperatures as low as 750 °C, significantly lower than those typically required for the product formation by TCVD.