Microwave purification of multi-wall carbon nanotubes in gas phase

Zheng, Jia; Bao, Rui; Yi, Jianhong; Yang, Ping

doi:10.1016/j.diamond.2016.06.006

Cited by 13 publications

(5 citation statements)

References 37 publications

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“…After acid treatment, the metals (Catalysts particle) and amorphous carbon products were dissolved in acid solution due to the acid attack. The crystalline carbon products were free from catalyst [26][27][28] materials. The crystalline carbon samples were suspended in ethanol solution and sonicated for 10 min.…”

Section: Purify Mwcntsmentioning

confidence: 99%

Effect of chemical vapor deposition parameters on the diameter of multi-walled carbon nanotubes

et al. 2018

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The multi-walled carbon nanotubes (MWCNTs) with controlled diameter distribution are useful in the fabrication of composite materials as reinforcement, due to their superior strength and toughness. Chemical vapor deposition (CVD) is a viable process to synthesize MWCNTs. In this investigation, an attempt has been made to study the effect of CVD process parameters (reaction temperature, flow rate of precursor gas, process time) on the mean diameter of MWCNTs. The MWCNTs of controlled diameter distribution was selectively grown on NiO catalyst supported by Al 2 O 3 nano particles. The argon and acetylene were used as carrier and carbon precursor gas, respectively. The catalyst and carbon samples were characterized using field emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy and thermogravimetric/differential thermal analysis. From this investigation, it is understood that the increase in reaction temperature and flow rate of precursor gas increased the mean diameter of MWCNTs but increase in process time decreased the diameter. The diameter distribution and quality of MWCNTs are strongly influenced by the diameter of the catalyst particles.

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Section: Purify Mwcntsmentioning

confidence: 99%

Effect of chemical vapor deposition parameters on the diameter of multi-walled carbon nanotubes

et al. 2018

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“…It is reasonable that during the lengthy thermal annealing process the graphitic network has a higher risk of damage or extending pre-existing defects, which is highly dependent on the local surroundings. , In contrast, for the MW activation case, the formation of hole defects in the short term would be kinetically inhibited. Taken together, the above results demonstrate that the MW irradiation method not only afforded a time-saving and energy-efficient (inset of Figure S8) route to create active sites but also importantly induced minimal damage to the graphitic network and could even efficiently purify CNTs …”

Section: Resultsmentioning

confidence: 65%

“…Taken together, the above results demonstrate that the MW irradiation method not only afforded a time-saving and energy-efficient (inset of Figure S8) route to create active sites but also importantly induced minimal damage to the graphitic network and could even efficiently purify CNTs. 33 As vapor grafting of monomers on CNTs (step 2) is, theoretically, a free radical polymerization process, modulation of the grafting time is the most direct and simple approach to tailor the mass ratio of the functional group. The employed parent CNT sponges initially appeared to be hydrophilic and could easily absorb water droplets (Figure S11), which resulted from the porous architecture and pre-existing defects and carbonaceous impurities (e.g., atom vacancies and oxygencontaining groups).…”

Section: Resultsmentioning

confidence: 99%

A Microwave-Assisted, Solvent-Free Approach for the Versatile Functionalization of Carbon Nanotubes

et al. 2023

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While the functionalization of carbon nanotubes (CNTs) has attracted extensive interest for a wide range of applications, a facial and versatile strategy remains in demand. Here, we report a microwave-assisted, solvent-free approach to directly functionalize CNTs both in raw form and in arbitrary macroscopic assemblies. Rapid microwave irradiation was applied to generate active sites on the CNTs while not inducing excessive damage to the graphitic network, and a gas-phase deposition afforded controllable grafting for thorough or regioselective functionalization. Using methyl methacrylate (MMA) as a model functional group and a CNT sponge as a model assembly, homogeneous grafting was exhibited by the increased robust hydrophobicity (contact angle increase from 30 to 140°) and improved structural stability (compressive modulus increased by 135%). Therefore, when our MMA-functionalized CNTs served as a solar absorber for saline distillation, high operating stability with a superior water evaporation rate of ∼2.6 kg m–2 h–1 was observed. Finally, to highlight the efficacy and versatility of this functionalization approach, we fabricated asymmetrically hydrophobic CNT sponges by regioselective functionalization to serve as a moisture-driven generator, which demonstrated a stable open-circuit voltage of 0.6 mV. This versatile, solvent-free approach can complement conventional solution-based techniques in the design and fabrication of multifunctional nanocarbon-based materials.

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“…It can be seen from the results that the intensity ratio of the D to G modes basically did not change after sintering, indicating that the structural integrity of the CNTs was well preserved. Slightly different from the case of composite powders after SBM, the G-band of CNTS in the composite material slightly shifted to a higher wavenumber, and such a peak shift has been attributed to the structural change of CNTs during processing [16,17], the bonding condition, and even the infiltration of metal atoms in CNTs [18,19].…”

Section: Resultsmentioning

confidence: 99%

A Comparison Study of Ag Composites Prepared by Spark Plasma Sintering and Hot Pressing with Silver-Coated CNTs as the Reinforcements

Dong-ming

Gan

et al. 2019

Materials

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In this study, carbon nanotube-reinforced silver composites (CNT/Ag) were prepared by the powder metallurgy process via spark plasma sintering (SPS) and hot pressing sintering (HP) with composite powders through an improved electroless plating method assisted by ultrasonic spray atomization. The dispersion of CNTs was effectively improved by ultrasonic spray atomization, and uniform silver layers were deposited on the surface of CNTs by electroless deposition. The property testing results showed significant improvements of the electrical conductivity, hardness, and tensile strength in the samples prepared by SPS, as compared to their HP sintered counterparts. When the volume fraction of CNTs reached 2.5%, the tensile strength reached a maximum value of 221 MPa, which was more than twice that of the pure silver samples. The structural analysis indicated different degrees of CNT agglomeration and matrix mean grain sizes in the composites prepared by SPS and HP, which are responsible for the differences in properties.

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Microwave purification of multi-wall carbon nanotubes in gas phase

Cited by 13 publications

References 37 publications

Effect of chemical vapor deposition parameters on the diameter of multi-walled carbon nanotubes

Effect of chemical vapor deposition parameters on the diameter of multi-walled carbon nanotubes

A Microwave-Assisted, Solvent-Free Approach for the Versatile Functionalization of Carbon Nanotubes

A Comparison Study of Ag Composites Prepared by Spark Plasma Sintering and Hot Pressing with Silver-Coated CNTs as the Reinforcements

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