Effect of nitrogen and hydrogen on the growth of multiwall carbon nanotubes on flexible carbon cloth using thermal chemical vapor deposition

Cheng, Teng

doi:10.1016/j.matchemphys.2012.06.043

Cited by 21 publications

(5 citation statements)

References 32 publications

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“…However, no CNT growth was observed with a H 2 /Ar ratio higher than 1.2 L h −1 /0.5 L h −1 (and thus a higher H 2 /cyclohexane ratio, Supporting Information File 1, Figure S2f), while Figure S2e shows only few CNTs and large amounts of surrounding (probably amorphous) carbon obtained with a smaller H 2 /Ar ratio (1.0 L h −1 /0.7 L h −1 ). It was reported that the density and diameter of CNTs synthesized on carbon cloth with ethylene as the carbon precursor over a nickel catalyst at 700 °C decrease with decreasing ratio of H 2 to N 2 [62], while CNTs grown on an Fe-decorated Si wafer at 825 °C using toluene increased in density and diameter with decreasing ratio of H 2 /Ar [63]. This demonstrates that the CNT growth strongly depends on the growth conditions.…”

Section: Resultsmentioning

confidence: 95%

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

Wang

Kulp

Bron

2019

Beilstein J. Nanotechnol.

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Hierarchically structured 3-dimensional electrodes based on branched carbon nanotubes (CNTs) are prepared on a glassy carbon (GC) substrate in a sequence of electrodeposition and chemical vapor deposition (CVD) steps as follows: Primary CNTs are grown over electrodeposited iron by CVD followed by a second Fe deposition and finally the CVD growth of secondary CNTs. The prepared 3-dimensional CNT structures (CNT/CNT/GC) exhibit enhanced double-layer capacitance and thus larger surface area compared to CNT/GC. Pt electrodeposition onto both types of electrodes yields a uniform and homogeneous Pt nanoparticle distribution. Each preparation step is followed by scanning electron microscopy, while the CNTs were additionally characterized by Raman spectroscopy. In this way it is demonstrated that by varying the parameters during the electrodeposition and CVD steps, a tuning of the structural parameters of the hierarchical electrodes is possible. The suitability of the hierarchical electrodes for electrocatalytic applications is demonstrated using the methanol electro-oxidation as a test reaction. The Pt mass specific activity towards methanol oxidation of Pt-CNT/CNT/GC is approximately 2.5 times higher than that of Pt-CNT/GC, and the hierarchical electrode exhibits a more negative onset potential. Both structures demonstrate an exceptionally high poisoning tolerance.

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Section: Resultsmentioning

confidence: 95%

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

Wang

Kulp

Bron

2019

Beilstein J. Nanotechnol.

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“…Agglomeration of the unreacted catalyst can clearly be seen in SEM and TEM micrographs at flowrates less than 100 sccm. The carbon deficiency resulted in defective nanotubes, which were broken and bent in an irregular manner [18][19][20][21].…”

Section: Resultsmentioning

confidence: 99%

“…Raman spectroscopy is also a useful tool to study the crystallinity the nanotubes [19]. The Raman spectra of the samples, produced with different ethylene flowrates, are shown in Figure 8.…”

Section: Resultsmentioning

confidence: 99%

Effect of Gas Flowrate on Nucleation Mechanism of MWCNTs for a Compound Catalyst

Shukrullah

Mohamed

Khan

et al. 2017

Journal of Nanomaterials

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Activation of the catalyst particles during a CVD process can be anticipated from the carbon feeding rate. In this study, Fe 2 O 3 /Al 2 O 3 catalyst was synthesized with uniformly dispersed iron over alumina support for onward production of multiwalled carbon nanotubes (MWCNTs) in a fluidized bed chemical CVD reactor. The effect of the ethylene flowrate on catalytic activity of the compound catalyst and morphology of the as-grown MWCNTs was also investigated in this study. The dispersed active phases of the catalyst and optimized gas flowrate helped in improving the tube morphology and prevented the aggregation of the as-grown MWCNTs. The flowrates, below 100 sccm, did not provide sufficient reactants to interact with the catalyst for production of defectfree CNT structures. Above 100 sccm, concentration of the carbon precursor did not show notable influence on decomposition rate of the gas molecules. The most promising results on growth and structural properties of MWCNTs were gained at ethylene flowrate of 100 sccm. At this flowrate, the ratio of and intensity peaks ( / ) was deliberated about 1.40, which indicates the growth of graphitic structures of MWCNTs.

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“…In the past few decades, carbon nanotubes (CNTs) have received intense research interests because of their desirable mechanical, optical, electrical and thermal properties [1]. In general, methane [2][3][4], ethylene [5][6][7][8], acetylene [4,[9][10][11] and other hydrocarbons have been used as carbon sources for CNT synthesis. Apart from these hydrocarbons, the use of waste polymers feedstock is more environmental and economical feedstock for CNT synthesis, hence transforming waste polymers into high value-added CNTs is desirable.…”

Section: Introductionmentioning

confidence: 99%

Preparation of multi‐walled carbon nanotubes and its application as flame retardant for polypropylene

Shen

Gong

et al. 2015

Micro & Nano Letters

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NiO catalyst supported on Fe-pillared montmorillonite (5-15 wt% Ni) was prepared via a simple conventional impregnation method. The physicochemical properties of the Ni catalyst were characterised by X-ray diffraction, inductively coupled plasma-atomic emission spectrometry and transmission electron microscopy. The Ni catalyst, together with organic montmorillonite (OMMT), was employed to prepare multi-walled carbon nanotubes (MWCNTs) by using polypropylene (PP) as a precursor. An increase in Ni loading of the catalyst led to a significant increase in the yield of MWCNTs at the expense of a slight decline in quality of the obtained MWCNTs. Moreover, OMMT altered the degradation process of PP, which resulted in a much higher fraction of light hydrocarbons in degradation products. As such, a substantial increase in the yield of MWCNTs was attained. In addition, the obtained MWCNTs were used as flame retardant for PP, and significantly enhanced thermal stability and flame retardancy according to thermogravimetry analysis and cone data, respectively. PP/MWCNTs nanocomposite exhibited higher degradation temperature, longer ignition time, much lower heat release rate and smoke production rate. This work offers an efficient Ni catalyst to convert PP into MWCNTs which could be applied as flame retardant for polymers.

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Effect of nitrogen and hydrogen on the growth of multiwall carbon nanotubes on flexible carbon cloth using thermal chemical vapor deposition

Cited by 21 publications

References 32 publications

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

Effect of Gas Flowrate on Nucleation Mechanism of MWCNTs for a Compound Catalyst

Preparation of multi‐walled carbon nanotubes and its application as flame retardant for polypropylene

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