Synthesis, Atomic Structures and Properties of Boron Nitride Nanotubes

Oku, Takeo

doi:10.5772/51968

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…where w is the BNNT displacement along the radial direction, Y s is the surface circumferential elastic modulus of the tube which depends on the chirality and size of the nanotube, ρh = 0.736 × 10 −7 g/cm 2 [21] is the mass density per unit lateral area of the BNNT and R is the average radius of the BNNT and is given by [22]…”

Section: Rbm Frequencymentioning

confidence: 99%

“…The RBM of the BNNTs corresponds to synchronous vibration of all atoms in a phase perpendicular to the tube axis, as if the tube were ‘breathing’. Therefore, the symmetric in‐phase vibration of all atoms of the BNNT in the radial direction can be governed by [20]

\frac{Y_{normals}}{R^{2}} w + ρ h \frac{\partial^{2} w}{\partial t^{2}} = 0

where w is the BNNT displacement along the radial direction, Y s is the surface circumferential elastic modulus of the tube which depends on the chirality and size of the nanotube, ρh =

0.736 \times 1 0^{- 7}

g/cm 2 [21] is the mass density per unit lateral area of the BNNT and R is the average radius of the BNNT and is given by [22]

R = \frac{r_{1}}{2 π} \sqrt{3 false(n^{2} + m n + m^{2} false)}

Here r 1 = 0.144 nm is the average B‐N bond length. The surface circumferential elastic modulus of ( n , m ) BNNT is obtained from a previously reported elastic modulus in [23].…”

Section: Rbm Frequencymentioning

confidence: 99%

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Raman radial breathing mode frequency of boron nitride nanotubes with bounded uncertain material properties

Ghavanloo

Fazelzadeh

2015

Micro & Nano Letters

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This Letter presents an analytical formulation for predicting the radial breathing mode (RBM) frequency of boron nitride nanotubes (BNNTs) with arbitrary chirality. Accurate material properties of the BNNTs are usually not available and the values of the material properties have certain amount of scatter, and some level of uncertainty. In the present investigation, the convex modelling is utilised to consider the bounded uncertain material properties in calculating the RBM frequency of the BNNTs. The results are compared with available data in the literature. Present study may provide useful information on the RBM frequency of the BNNTs with arbitrary chirality in practical applications.

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Section: Rbm Frequencymentioning

confidence: 99%

\frac{Y_{normals}}{R^{2}} w + ρ h \frac{\partial^{2} w}{\partial t^{2}} = 0

where w is the BNNT displacement along the radial direction, Y s is the surface circumferential elastic modulus of the tube which depends on the chirality and size of the nanotube, ρh =

0.736 \times 1 0^{- 7}

g/cm 2 [21] is the mass density per unit lateral area of the BNNT and R is the average radius of the BNNT and is given by [22]

R = \frac{r_{1}}{2 π} \sqrt{3 false(n^{2} + m n + m^{2} false)}

Here r 1 = 0.144 nm is the average B‐N bond length. The surface circumferential elastic modulus of ( n , m ) BNNT is obtained from a previously reported elastic modulus in [23].…”

Section: Rbm Frequencymentioning

confidence: 99%

Raman radial breathing mode frequency of boron nitride nanotubes with bounded uncertain material properties

Ghavanloo

Fazelzadeh

2015

Micro & Nano Letters

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“…h-BN monolayer has similar geometric structure to that of graphene but it is an insulator with a wide band gap (˜5.8 eV) 18 . It is, however, theoretically demonstrated the band gap of h-BN monolayer can be considerably reduced if some defects are introduced and/or it is placed on metal substrates 19 20 and it is experimentally shown that the atomically thin h-BN nanoribbons become semiconducting 21 similar to metal dichalcogenides. Furthermore, hydrogen adsorption/storage ability of BN has been experimentally demonstrated 22 23 .…”

mentioning

confidence: 99%

Highly Efficient Electrochemical Hydrogen Evolution Reaction at Insulating Boron Nitride Nanosheet on Inert Gold Substrate

Uosaki

Elumalai

Dinh

et al. 2016

Sci Rep

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It is demonstrated that electrochemical hydrogen evolution reaction (HER) proceeds very efficiently at Au electrode, an inert substrate for HER, modified with BNNS, an insulator. This combination has been reported to be an efficient electrocatalyst for oxygen reduction reaction. Higher efficiency is achieved by using the size controlled BNNS (<1 μm) for the modification and the highest efficiency is achieved at Au electrode modified with the smallest BNNS (0.1–0.22 μm) used in this study where overpotentials are only 30 mV and 40 mV larger than those at Pt electrode, which is known to be the best electrode for HER, at 5 mAcm−2 and at 15 mAcm−2, respectively. Theoretical evaluation suggests that some of edge atoms provide energetically favored sites for adsorbed hydrogen, i.e., the intermediate state of HER. This study opens a new route to develop HER electrocatalysts.

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“…During CVD-based BNNT growth, the pre-added "catalysts" react with boron (B, B 2 O 3 , and H 3 BO 3 ) or nitrogen (NH 3 and N 2 ) precursors, forming a variety of chemical species such as metal, metal oxides, metal borides, metal nitrides, and metal borates. [14,28] The complexity of the reactions during CVD-based BNNT growth makes it difficult to identify the true catalyst, resulting in low growth efficiency and uncontrolled synthesis. Terao et al [24] reported that magnesium (Mg) droplets served as catalysts in BNNT growth with a mixture of B and magnesium oxide (MgO) as the source material.…”

Section: Introductionmentioning

confidence: 99%

Growth of Boron Nitride Nanotube Over Al‐Based Active Catalyst and its Application in Thermal Management

Ding

et al. 2023

Small Structures

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The effective identification of the active catalytic phase is essential to elucidate the growth mechanism of boron nitride nanotubes (BNNTs) and realize their controllable and scalable synthesis. However, owing to the complexity of chemical reactions during BNNT growth via chemical vapor deposition (CVD) and the lack of techniques for in situ characterization at high temperatures (1100–1300 °C), identifying the true catalyst during BNNT growth is challenging. Herein, an aluminum (Al)‐based active catalyst for BNNT growth via CVD is investigated. The initial Al2O3 nanoparticle catalyst precursor is transformed into an Al‐B phase prior to BNNT growth. Based on our density functional theory‐based molecular dynamic simulations of BNNT nucleation, AlB x (x = 1.5 to 2) shows catalytic activity for the formation of BN chains and BN six‐membered rings. Confirmatory experiments demonstrate that AlB2 is the active Al‐based catalyst during BNNT growth. A nanocomposite is prepared from cellulose nanocrystal, and purified BNNTs exhibited a high in‐plane thermal conductivity of 13.33 W m−1 K−1 at 20 wt% BNNTs. A further application for light‐emitting diode chip cooling demonstrates excellent heat‐dissipation performance of the nanocomposite film. Thus, this study can guide the controllable synthesis of high‐quality BNNTs and facilitate their use in thermal interface materials.

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Synthesis, Atomic Structures and Properties of Boron Nitride Nanotubes

Cited by 8 publications

References 19 publications

Raman radial breathing mode frequency of boron nitride nanotubes with bounded uncertain material properties

Raman radial breathing mode frequency of boron nitride nanotubes with bounded uncertain material properties

Highly Efficient Electrochemical Hydrogen Evolution Reaction at Insulating Boron Nitride Nanosheet on Inert Gold Substrate

Growth of Boron Nitride Nanotube Over Al‐Based Active Catalyst and its Application in Thermal Management

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