Effect of electrochemical treatment on structural properties of conical carbon nanotubes

Khantimerov, S. M.; Shustov, V. A.; Kurbatova, N. V.; Kukovitsky, E. F.; Матухин, В. Л.; Sakhratov, Yu. A.; Suleimanov, N. M.

doi:10.1007/s00339-013-7697-0

Cited by 6 publications

(5 citation statements)

References 27 publications

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“…After that acid was evaporated and treated CNTs were rinsed with distilled water, filtered, and dried at 105 ∘ C. X-ray diffraction and electron spin resonance (ESR) experiments were carried out to study the as-prepared and treated with nitric acid CNTs. The results on X-ray diffraction experiments were the same as we described previously [15] and the effectiveness of acid treatment for the removal of residual catalyst particles was shown. Figure 4.…”

Section: Methodssupporting

confidence: 56%

“…Hydrogenation of carbon nanotubes was performed using galvanostatic method in a three-electrode cell as described previously [15]. After hydrogenation the sample was rinsed with distilled water, filtered, and dried at 120 ∘ C for one hour to remove physically adsorbed molecules from the surface.…”

Section: Methodsmentioning

confidence: 99%

“…Conical CNTs have a unique feature: the majority of their internal and external edges are open and this is favorable for hydrogen intercalation into their interplanar spaces. Previously, it was shown [15] that electrochemical hydrogen sorption leads to the structural changes occurring during hydrogenation in the conical walls of the CNTs. Such changes were associated with the hydrogen intercalation into the interplanar spaces of conical CNTs and its addition to the -bonds of graphite layers.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Electrochemical Treatment on Electrical Conductivity of Conical Carbon Nanotubes

Khantimerov

Togulev

Kukovitsky

et al. 2016

Journal of Nanotechnology

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Interaction of conical carbon nanotubes (CNTs) with hydrogen during electrochemical treatment and its effect on their electronic properties was studied. The temperature dependencies of electroconductivity of initial and electrochemically hydrogenated conical CNTs were investigated by using four-probe van der Pauw method. The studies revealed that the electrochemical hydrogen absorption leaded to a significant reduction in the electroconductivity of conical carbon nanotubes. We assume that these changes can be associated with a decrease in the concentration of charge carriers as a result of hydrogen localization on the carbon π-orbitals, the transition from sp2 to sp3 hybridization of conical CNTs band structure, and, therefore, a metal-semiconductor-insulator transition.

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Section: Methodssupporting

confidence: 56%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Electrochemical Treatment on Electrical Conductivity of Conical Carbon Nanotubes

Khantimerov

Togulev

Kukovitsky

et al. 2016

Journal of Nanotechnology

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“…It is known that nanoparticles are quite expensive formations, the use of which can harm the environment. Therefore, we chose carbon nanotubes (CNT) as nanoparticles, which have already been used with great success in various fields of power engineering [18,19]. Despite the fact that carbon nanotubes are non biodegradable nanoparticles, they completely burn out together with fuel, because they consist of pure carbon, and their catalytic properties lead to a more complete combustion of the other components of the fuel, which may be important for eliminating the negative consequences of heavy fuel using.…”

Section: The Methods In Generalmentioning

confidence: 99%

Methods and Materials of Nanotechnologies for Improving the Boiler Fuel Properties

Zvereva

Makarova

Зуева

2018

SSP

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It was shown that nanotechnology methods and materials can be used to create a composite fuel with improved performance characteristics. To reduce the viscosity of various types of hydrocarbon fuel, small amounts of nanoparticles can be added, leading to an additional structure formation, which may result in a change in the rheological properties due to the transition to layerwise shear flow. The possibilities of using carbon nanotubes and dehydrated carbonate sludge of water treatment were analyzed. The presence of a synergistic effect in the joint application of carbon nanotubes with carbonate sludge has been established. It has been shown that the choice of corresponding nanoparticles and their dispersion medium for a particular type of hydrocarbon fuel can significantly improve its performance characteristics.

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“…External morphology and internal microstructure of individual nanotubes obtained in identical CVD processes were studied in detail in our previous works by high resolution electron microscopy 44 and Raman analysis. 45,46 They are typical for the so called fishbone nanotubes (nanofibres) and not shown here. The white spots in Fig.…”

Section: M57mentioning

confidence: 99%

Surface Integrity and Carbon Chemical Vapor Deposition on Nickel Foil: Surface Abrasive Treatment

Kukovitsky

L’vov

Shustov

et al. 2015

ECS J. Solid State Sci. Technol.

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Carbon chemical vapor deposition on bulk nickel surfaces generated by abrasive treatment was experimentally studied. Initial stages of deposition were closely examined to elucidate possible effect on the formation and properties of carbon nanotube layers grown directly on bulk metal substrates. Two main phenomena complicate graphite-like carbon deposition on rough nickel surface in comparison with the perfect one. The first phenomenon is the rate increase of carbon formation at surface defects including small confined spaces with large surface-to-volume ratio (pits, gaps, cracks, etc.). Small cavities in subsurface layer are also places of enhanced carbon formation. The cause of this increase is the specific chemistry of hydrocarbon pyrolysis in the conditions of prolonged residence time realized in confined space. The high rate of carbon formation leads to fast growth of highly disordered (coke-like) graphite carbon inside such defects. The second phenomenon is the fast metal dusting of micron-sized surface asperities formed by plastically deformed metal and generated by abrasive treatment. Numerous micro-cracks created on surface in course of metal dusting promote the first phenomenon becomes operative. It was proposed that the roughness of catalytically active surface can be the cause of pyrolysis surface chemistry change comparing with smooth surface.Catalytic carbon deposition on bulk metal surface during hydrocarbon pyrolysis is dependent on a number of variables. Reaction temperature, gas chemical nature and pressure are known to be important factors. 1,2 The chemical nature of the catalyst (e.g., alloy) also plays a role. 3 The carbon activity in the gas phase determines whether carbide can form from a particular catalyst metal. Carbide formation in some catalyst metals is believed to have an influence on fragmentation and the creation of filaments. 4 Duration of reaction is also important, as one form of carbon can be produced at first, with another form appearing after longer reaction times. 5 Hydrogen partial pressure has been known to impact significantly the rate at which carbon forms. 6 Hydrogen has also a significant effect on the form of carbon deposited. 5 Many other factors, such as reactive gas transport conditions 7,8 and the surface state of the metal, can have a profound effect on metal ability to catalyze the formation of carbon during a hydrocarbon conversion process. The same factors determine the rate of carbon deposition and deposit morphology. Some works touched upon the effect of metal surface state and surface topographic imperfections on carbon deposition. It has been noted earlier that surface graphite nucleates preferentially at substrate edges, kink sites and surface steps. 9,10 Initial formation of carbon was shown to be larger over the unpolished foil, as would be expected if topographical imperfections are preferential sites for graphite nucleation. 11 The similar results were noticed in more recent works. Microscopic observations revealed that some of the carbons were actuall...

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Effect of electrochemical treatment on structural properties of conical carbon nanotubes

Cited by 6 publications

References 27 publications

Effect of Electrochemical Treatment on Electrical Conductivity of Conical Carbon Nanotubes

Effect of Electrochemical Treatment on Electrical Conductivity of Conical Carbon Nanotubes

Methods and Materials of Nanotechnologies for Improving the Boiler Fuel Properties

Surface Integrity and Carbon Chemical Vapor Deposition on Nickel Foil: Surface Abrasive Treatment

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