Molecular Evolutionary Growth of Ultralong Semiconducting Double‐Walled Carbon Nanotubes

Gao, Jun; Jiang, Yaxin; Chen, Sibo; Yue, Hongjie; He, Rong; Zhu, Zhenxing; Wei, Fei

doi:10.1002/advs.202205025

Cited by 3 publications

(1 citation statement)

References 46 publications

(59 reference statements)

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“…For conventional ultralong CNT arrays, the collection of Raman spectra is usually conducted on air-suspended isolated CNTs due to their extremely low areal densities, that is, the spacings between CNTs are much larger than the spot size of the excitation laser (usually 1 μm). [59,60] However, in this work, the highest areal density of the FeCu-catalyzed ultralong CNT arrays reached ≈8100 CNTs mm −1 , leading to much smaller spacings between CNTs than the spot size of the excitation laser. In this way, Raman scattering signals from multiple CNTs could be simultaneously obtained in a single acquisition, which was beneficial for the statistical investigation of the structures of ultralong CNTs with high efficiency (inset of Figure 5c).…”

Section: Resultsmentioning

confidence: 61%

Floating Bimetallic Catalysts for Growing 30 cm‐Long Carbon Nanotube Arrays with High Yields and Uniformity

Jiang,

Wu,

Wang

et al. 2024

Advanced Materials

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Ultralong carbon nanotubes (CNTs) are considered as promising candidates for many cutting‐edge applications. However, restricted by the extremely low yields of ultralong CNTs, their practical applications can hardly be realized. Therefore, new methodologies should be developed to boost the growth efficiency of ultralong CNTs and alleviate their areal density decay at the macroscale level. Herein, a facile, universal, and controllable method for the in‐situ synthesis of floating bimetallic catalysts (FBCs) is proposed to grow ultralong CNT arrays with high yields and uniformity. Ferrocene and metal acetylacetonates serve as catalyst precursors, affording the successful synthesis of a series of FBCs with controllable compositions. Among these FBCs, the optimized FeCu catalyst increases the areal density of ultralong CNT arrays to a record‐breaking value of ∼8100 CNTs mm–1, and exhibits a lifetime 3.40 times longer than that of Fe, thus achieving both high yields and uniformity. A 30‐centimeters‐long and high‐density ultralong CNT array is also successfully grown with the assistance of FeCu catalysts. As evidenced by our kinetic model and molecular dynamics simulations, the introduction of Cu into Fe can simultaneously improve the catalyst fluidity and decrease carbon solubility, and an optimal catalytic performance will be achieved by balancing this tradeoff.This article is protected by copyright. All rights reserved

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Section: Resultsmentioning

confidence: 61%

Floating Bimetallic Catalysts for Growing 30 cm‐Long Carbon Nanotube Arrays with High Yields and Uniformity

Jiang,

Wu,

Wang

et al. 2024

Advanced Materials

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Molecular Evolutionary Growth of Ultralong Semiconducting Double‐Walled Carbon Nanotubes

et al. 2022

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The self-assembling preparation accompanied with template auto-catalysis loop and the ability to gather energy, induces the appearance of chirality and entropy reduction in biotic systems. However, an abiotic system with biotic characteristics is of great significance but still missing. Here, it is demonstrated that the molecular evolution is characteristic of ultralong carbon nanotube preparation, revealing the advantage of chiral assembly through template auto-catalysis growth, stepwise-enriched chirality distribution with decreasing entropy, and environmental effects on the evolutionary growth. Specifically, the defective and metallic nanotubes perform inferiority to semiconducting counterparts, among of which the ones with double walls and specific chirality (n, m) are more predominant due to molecular coevolution. An explicit evolutionary trend for tailoring certain layer chirality is presented toward perfect near-(2n, n)-containing semiconducting double-walled nanotubes. These findings extend our conceptual understanding for the template auto-catalysis assembly of abiotic carbon nanotubes, and provide an inspiration for preparing chiral materials with kinetic stability by evolutionary growth.

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Innovative reinforcement method for metal foam cell wall using CNTs

Cilsal,

Lekesiz,

Cakir

2024

Nanotechnology

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Carbon nanotubes (CNTs) and their composites are gaining popularity due to their exceptional strength qualities. It is well known that adding carbon nanotubes to metal foam composites boosts compressive strength. On the other hand CNT addition is still a costly process due to high cost of the CNTs. This study presents a novel and cost-effective solution by selectively adding CNTs to the structurally weakest regions of aluminum foam materials produced via powder metallurgy, employing a newly developed focused multi-step additive method. The cell borders of aluminum foam are strengthened with multiple spherical layers of CNTs, using a transfer method by initially coating the space holders used at the foaming process. The strength increase effect of this CNT addition method was compared with the widely known aluminum foam production parameters via a 4-parameter design of experiment (DOE) study. Compressive strength values of the samples were evaluated using a constant speed compression test acc. to ISO13314. The compacting pressure, CNT concentration, sintering temperature, and sintering period were chosen as design of experiment parameters, and 78% of the interactions effecting on final compressive strength could be explained with the model. As a result, it was established that, compared to the other parameters, sintering duration had the highest influence on compressive strength. But besides It has also been shown that adding 0.53% CNT by weight only to the cell border regions increases overall strength by 9%. This weight-strength increase ratio is compared with similar studies in the literature and found to be providing a production cost advantage due to the lower amount of CNT addition requirement for the comparable weight relative strength increase. Focused strength increase method has potential to enable controlled failure of foam materials by selectively strengthening strength critical areas of a component.

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Molecular Evolutionary Growth of Ultralong Semiconducting Double‐Walled Carbon Nanotubes

Cited by 3 publications

References 46 publications

Floating Bimetallic Catalysts for Growing 30 cm‐Long Carbon Nanotube Arrays with High Yields and Uniformity

Floating Bimetallic Catalysts for Growing 30 cm‐Long Carbon Nanotube Arrays with High Yields and Uniformity

Molecular Evolutionary Growth of Ultralong Semiconducting Double‐Walled Carbon Nanotubes

Innovative reinforcement method for metal foam cell wall using CNTs

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