Nontronites as catalyst for synthesis of carbon nanotubes by catalytic chemical vapor deposition.

Kavecký, Štefan; Valúchová, Jana; Čaplovičová, Mária; Heißler, Stefan; Šajgalı́k, Pavol; Janek, M.

doi:10.1016/j.clay.2015.06.001

Cited by 12 publications

(6 citation statements)

References 49 publications

(45 reference statements)

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“…We have considered the Raman spectra of nontronite in more detail, since many research studies are now related to the study of the growth of multi-waved carbon nanotubes on natural clay minerals and their potential use as catalysts, substrates, and templates. [59][60][61] The Raman spectrum of nontronite from the Salair Ridge weathered crust is shown for comparison (Figure 4). Only the visible and near-ultraviolet wavelength laser excitation yielded the Raman spectra for this Salair nontronite ( Table 2).…”

Section: Methodsmentioning

confidence: 99%

“…[4,10,63] The layered structure of the nontronite leads to the formation of graphites of unusual morphology as well as the formation of various forms of synthetic multilayered carbon nanotubes (MCNT). [59][60][61] These carbon nanotubes have been synthesized in the temperature range from 500 to 700°C. [59] Carbon nanotubes with different morphologies and diameters in which smectite and nontronite were used as a catalyst, as substrates, and as a template were obtained.…”

Section: Salairmentioning

confidence: 99%

“…[59][60][61] These carbon nanotubes have been synthesized in the temperature range from 500 to 700°C. [59] Carbon nanotubes with different morphologies and diameters in which smectite and nontronite were used as a catalyst, as substrates, and as a template were obtained. [60,61,67,68] The interlayer hydrogen bonding of the nontronite structure imposes a definite stacking of the layers, which results in strict crystallographic control of the resulting nanostructures.…”

Section: Salairmentioning

confidence: 99%

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Raman spectra of a graphite–nontronite association in marbles from Oltrek Island (Lake Baikal, Russia)

Мороз

Edwards

Пономарчук

et al. 2019

J Raman Spectroscopy

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The graphite in marbles from Oltrek, an uninhabited island on Lake Baikal, has been investigated by micro‐Raman spectroscopy using visible and near‐ultraviolet wavelength excitation. All graphite samples exhibit a sharp first‐order Raman band at about 1,580 cm−1 with a width from 10 to 19 cm−1, and sometimes a D1 band with very low intensity, which is occasionally absent. Using Raman spectra data it was estimated that the temperature of graphite formation in the Oltrek marbles is about 530–650°C and possibly even higher. This evaluation is in good agreement with the temperatures (about 700°C) determined by a graphite isotope geothermometer of the graphite–calcite pair. Scanning electron microscopy images have recorded a сonical graphite morphology on the surface of plate crystals of graphite. Raman spectra of samples with cones about 200–400 nm sizes showed that the graphite was associated with nontronite in the specimens studied. Natural nontronite, a clay mineral of the smectite group, has not been well characterized using Raman spectroscopy. Here, the Raman spectra of the Oltrek nontronite were compared with the spectrum of nontronite from the weathered crust of the Salair Ridge, Russia. The formation of hexagonal–pyramidal structures on the surface of graphite with the participation of clay and bio‐organic matter in marble is discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Salairmentioning

confidence: 99%

Section: Salairmentioning

confidence: 99%

See 1 more Smart Citation

Raman spectra of a graphite–nontronite association in marbles from Oltrek Island (Lake Baikal, Russia)

Мороз

Edwards

Пономарчук

et al. 2019

J Raman Spectroscopy

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show abstract

“…The measured and theoretical values of graphene conductivity are quite different, mainly because prepared graphene does not have a complete hexagonal honeycomb structure and there are some defects and an imperfect crystal lattice 20 , which is not conducive to electronic transmission. Carbon nanotubes (CNTs) are curled from one or more layers of graphene 21 , 22 . Graphene itself is an excellent conductive material, so CNTs also have good conductivity 23 .…”

Section: Introductionmentioning

confidence: 99%

Bilayer and three dimensional conductive network composed by SnCl2 reduced rGO with CNTs and GO applied in transparent conductive films

Tian

Guo

Wang

et al. 2021

Sci Rep

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Graphene oxide (GO), reduced graphene oxide (rGO) and carbon nanotubes (CNTs) have their own advantages in electrical, optical, thermal and mechanical properties. An effective combination of these materials is ideal for preparing transparent conductive films to replace the traditional indium tin oxide films. At present, the preparation conditions of rGO are usually harsh and some of them have toxic effects. In this paper, an SnCl2/ethanol solution was selected as the reductant because it requires mild reaction conditions and no harmful products are produced. The whole process of rGO preparation was convenient, fast and environmentally friendly. Then, SEM, XPS, Raman, and XRD were used to verify the high reduction efficiency. CNTs were introduced to improve the film conductive property. The transmittance and sheet resistance were the criteria used to choose the reduction time and the content ratios of GO/CNT. Thanks to the post-treatment of nitric acid, not only the by-product (SnO2) and dispersant in the film are removed, but also the doping effect occurs, which are all conducive to reducing the sheet resistances of films. Ultimately, by combining rGO, GO and CNTs, transparent conductive films with a bilayer and three-dimensional structure were prepared, and they exhibited high transmittance and low sheet resistance (58.8 Ω/sq. at 83.45 T%, 47.5 Ω/sq. at 79.07 T%), with corresponding $${{\sigma_{dc} } \mathord{\left/ {\vphantom {{\sigma_{dc} } {\sigma_{opt} }}} \right. \kern-\nulldelimiterspace} {\sigma_{opt} }}$$ σ dc / σ opt values of 33.8 and 31.8, respectively. In addition, GO and rGO can modify the surface and reduce the film surface roughness. The transparent conductive films are expected to be used in photoelectric devices.

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“…Correlation between the position of G band and the metamorphic temperature from experimental and referenced data (рис. 3, кривые 1, 2), так как известно, что использование нонтронита при синтезе многослойных углеродных нанотрубок ведет к формированию нанотрубок разной формы [11]. В других точках мы наблюдали КР спектры первого и второго порядка высокоупорядоченного графита (рис.…”

unclassified

Structural Peculiarities of Natural Carbonaceous Materials: Raman Spectroscopy Data

Мороз¹,

Goryaĭnov²,

Пономарчук³

2018

SJP

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Nontronites as catalyst for synthesis of carbon nanotubes by catalytic chemical vapor deposition.

Cited by 12 publications

References 49 publications

Raman spectra of a graphite–nontronite association in marbles from Oltrek Island (Lake Baikal, Russia)

Raman spectra of a graphite–nontronite association in marbles from Oltrek Island (Lake Baikal, Russia)

Bilayer and three dimensional conductive network composed by SnCl2 reduced rGO with CNTs and GO applied in transparent conductive films

Structural Peculiarities of Natural Carbonaceous Materials: Raman Spectroscopy Data

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