Kinetic study of single-walled carbon nanotube synthesis by thermocatalytic decomposition of methane using floating catalyst chemical vapour deposition

Yadav, Manishkumar D.; Dasgupta, Kinshuk; Patwardhan, Ashwin W.; Kaushal, Amit; Joshi, Jyeshtharaj B.

doi:10.1016/j.ces.2018.10.050

Cited by 38 publications

(40 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene, are exciting materials showing a combination of superior properties: lightness, thermal and electrical conductivity, and optical and mechanical properties . The technology of CNT synthesis, although in a continuous state of improvement, cannot avoid the use of catalysts to increase the conversion rate from carbon precursors to the production of carbon nanomaterials, as this rate is still far below 100%. − The presence of both metal and carbon impurities has negative effects on the CNT properties. , It is widely known that magnetic properties of CNTs are dominated by catalyst residues even at low content . Thermal and electrical conductivity and mechanical properties (tensile strength) are dramatically decreased because of carbon impurities in CNT samples .…”

Section: Introductionmentioning

confidence: 99%

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

et al. 2019

View full text Add to dashboard Cite

Purity of carbon nanotubes (CNTs) is essential to avoid a dramatic decrease in their performances. In addition to metallic impurities, carbonaceous impurities have been shown to be responsible for pronounced effects. However, they are highly difficult to be selectively removed from CNT samples because of the similar chemical reactivity of these two kinds of carbon species. The existing purification methods often lead to high CNT consumption (>90 wt %). The proposed method consists of a one-pot gas-phase treatment combining chlorine and oxygen. The CNT powder maintained in a chlorine stream is submitted to oxygen at moderate temperature [350 and 500°C for single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs), respectively], and the thermal treatment is then pursued at 900−1000°C under chlorine alone. Our work reveals that this approach is able to significantly improve the selectivity of elimination of carbonaceous impurities. Thanks to the proposed purification treatment, only 19 and 11 wt % of carbon species (mainly carbon impurities) are lost for DWCNTs and SWCNTs, respectively. The mechanism proposed involves a protective effect by grafting of chlorine favored to the CNT walls. Because our simple one-pot purification method is also versatile and scalable, it opens new perspectives for CNT applications in high-added value fields.

show abstract

Section: Introductionmentioning

confidence: 99%

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

et al. 2019

View full text Add to dashboard Cite

show abstract

“…74,75 On the other hand, according to various works on the kinetics of carbon nanotube formation, the dissociative adsorption of methane followed by the removal of hydrogen from the adsorbed methyl group limits the catalytic decomposition of methane. 70,72,73 The kinetic models presented in the latter works differ in the number of active site types. The kinetic models for double- 70 and single-walled 72 carbon nanotube synthesis are based on the presence of only one type of active sites, whereas that developed for the formation of multiwalled carbon nanotubes 73 considers two different types of active sites.…”

Section: Ch Chmentioning

confidence: 99%

“…70,72,73 The kinetic models presented in the latter works differ in the number of active site types. The kinetic models for double- 70 and single-walled 72 carbon nanotube synthesis are based on the presence of only one type of active sites, whereas that developed for the formation of multiwalled carbon nanotubes 73 considers two different types of active sites. Here, CH x * and H* species are adsorbed on different kinds of active sites.…”

Section: Ch Chmentioning

confidence: 99%

“…Several reaction mechanisms have been postulated to explain the catalytic pyrolysis reaction of methane. Some works have proposed a molecular adsorption mechanism (Scheme A), − whereas a dissociative adsorption model has been described in other studies (Scheme B). − In the molecular adsorption mechanism, methane is first adsorbed on the catalyst surface and then dissociates following a series of stepwise surface dehydrogenation reactions. Nevertheless, according to the dissociative adsorption model, methane dissociates upon adsorption on the catalytic active sites generating chemisorbed CH 3 and H fragments.…”

Section: Reaction Mechanism Of Methane Pyrolysismentioning

confidence: 99%

See 1 more Smart Citation

Methane Pyrolysis for Zero-Emission Hydrogen Production: A Potential Bridge Technology from Fossil Fuels to a Renewable and Sustainable Hydrogen Economy

Sanchez‐Bastardo

Schlögl

Ruland

2021

Ind. Eng. Chem. Res.

248

107

View full text Add to dashboard Cite

Hydrogen plays a key role in many industrial applications and is currently seen as one of the most promising energy vectors. Many efforts are being made to produce hydrogen with zero CO2 footprint via water electrolysis powered by renewable energies. Nevertheless, the use of fossil fuels is essential in the short term. The conventional coal gasification and steam methane reforming processes for hydrogen production are undesirable due to the huge CO2 emissions. A cleaner technology based on natural gas that has received special attention in recent years is methane pyrolysis. The thermal decomposition of methane gives rise to hydrogen and solid carbon, and thus, the release of greenhouse gases is prevented. Therefore, methane pyrolysis is a CO2-free technology that can serve as a bridge from fossil fuels to renewable energies.

show abstract

“…There are extensive reports on CMD using various catalysts such as transition metals (Fe, Ni, Cu, and Co), noble metals (Pd, Au, Pt, and Ir), metal oxides, and carbon (graphene and carbon nanotubes) and their composites [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Overall, the shape, composition, size, and surface features of the catalysts are the main factors determining catalytic performance towards CMD, which has attracted considerable attention in the last few years [ 18 , 19 , 20 , 21 ]. According to Scopus, more than 2000 articles have been devoted to CMD in the last five years ( Figure 1 ).…”

Section: Introductionmentioning

confidence: 99%

Catalytic Methane Decomposition to Carbon Nanostructures and COx-Free Hydrogen: A Mini-Review

et al. 2021

View full text Add to dashboard Cite

Catalytic methane decomposition (CMD) is a highly promising approach for the rational production of relatively COx-free hydrogen and carbon nanostructures, which are both important in multidisciplinary catalytic applications, electronics, fuel cells, etc. Research on CMD has been expanding in recent years with more than 2000 studies in the last five years alone. It is therefore a daunting task to provide a timely update on recent advances in the CMD process, related catalysis, kinetics, and reaction products. This mini-review emphasizes recent studies on the CMD process investigating self-standing/supported metal-based catalysts (e.g., Fe, Ni, Co, and Cu), metal oxide supports (e.g., SiO2, Al2O3, and TiO2), and carbon-based catalysts (e.g., carbon blacks, carbon nanotubes, and activated carbons) alongside their parameters supported with various examples, schematics, and comparison tables. In addition, the review examines the effect of a catalyst’s shape and composition on CMD activity, stability, and products. It also attempts to bridge the gap between research and practical utilization of the CMD process and its future prospects.

show abstract

Kinetic study of single-walled carbon nanotube synthesis by thermocatalytic decomposition of methane using floating catalyst chemical vapour deposition

Cited by 38 publications

References 61 publications

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

Methane Pyrolysis for Zero-Emission Hydrogen Production: A Potential Bridge Technology from Fossil Fuels to a Renewable and Sustainable Hydrogen Economy

Catalytic Methane Decomposition to Carbon Nanostructures and COx-Free Hydrogen: A Mini-Review

Contact Info

Product

Resources

About