Manufacturing and Processing of Carbon Nanotubes for H2 Storage

In pursuit of manufacturing of carbon nanotubes (CNTs) in good yield at lower temperatures, a mixture of d-block elements such as Iron, Nickel, and Cobalt was expected to be advantageous because of the high yield and low temperature (at 220 - 250° C) synthesis. The physical state and aggregation of these catalyst particles in the reaction medium have been found to play an interesting role in obtaining CNTs at better yield. Carbon nanotubes have been successfully produced by an uncomplicated two-step solvothermal method between sodium and dichlorobenzene via Ni/Fe/Co as catalyst precursor. The dependence of yield of CNTs on the catalyst system was determined via different ratios of catalysts and at various other experimental conditions such as different heating temperatures, different durations of heating. The X-ray powder diffraction study has indicated the graphite kind of the products. Microscopic characterizations (SEM and TEM) implied us the diameters of carbon nanotubes are 10-14 nm. Raman spectroscopy shows the presence of graphitized carbon in carbon nanotubes. Significant influence by the heating temperature and heating duration has been observed on the product yield.

Download Full-text

Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

Journal of Nanomaterials ◽

10.1155/2014/539295 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5

Author(s):

Daisuke Ogawa ◽

Ryo Kitaura ◽

Takeshi Saito ◽

Shinobu Aoyagi ◽

Eiji Nishibori ◽

...

Keyword(s):

Carbon Nanotubes ◽

High Yield ◽

Single Wall Carbon Nanotubes ◽

X Ray Diffraction ◽

Single Wall Carbon ◽

X Ray ◽

Transmission Electron ◽

Organometallic Molecules ◽

X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

Download Full-text

Efficient synthesis of carbon nanotubes with improved surface area by low-temperature solvothermal route from dichlorobenzene

Chemical Papers ◽

10.2478/s11696-013-0397-6 ◽

2013 ◽

Vol 67 (11) ◽

Cited By ~ 3

Author(s):

Gantigaiah Krishnamurthy ◽

Sarika Agarwal

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Carbon Source ◽

Surface Area ◽

Heating Temperature ◽

Outer Diameter ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Scanning Electron

AbstractThe synthesis of well-aggregated carbon nanotubes in the form of bundles was achieved by the catalytic reduction of 1,2-dichlorobenzene by a solvothermal approach. The use of 1,2-dichlorobenzene as a carbon source yielded a comparably good percentage of carbon nanotubes in the range of 60–70 %, at a low reaction temperature of 200°C. The products obtained were analysed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The X-ray diffraction studies implied the presence of pure, crystalline, and well-ordered carbon nanotubes. The scanning electron and transmission electron microscopic images revealed the surface morphology, dimensions and the bundled form of the tubes. These micrographs showed the presence of multi-walled carbon nanotubes with an outer diameter of 30–55 nm, inner diameter of 15–30 nm, and lengths of several hundreds of nanometers. Brunauer-Emmett-Teller-based N2 gas adsorption studies were performed to determine the surface area and pore volume of the carbon nanotubes. These carbon nanotubes exhibit a better surface area of 385.30 m2 g−1. In addition, the effects of heating temperature, heating time, amount of catalyst and amount of carbon source on the product yield were investigated.

Download Full-text

A Comparative Study of Carbon Nanotubes Synthesized from Co/Zn/Al and Fe/Ni/Al Catalyst

E-Journal of Chemistry ◽

10.1155/2011/252875 ◽

2011 ◽

Vol 8 (3) ◽

pp. 1014-1021 ◽

Cited By ~ 1

Author(s):

Ezekiel Dixon Dikio

Keyword(s):

Carbon Nanotubes ◽

Raman Spectroscopy ◽

Electron Microscope ◽

Thermogravimetric Analysis ◽

Catalyst System ◽

X Ray ◽

Transmission Electron ◽

Catalyst Systems ◽

Synthesis Of Carbon Nanotubes ◽

Scanning Electron

The catalyst systems Fe/Ni/Al and Co/Zn/Al were synthesized and used in the synthesis of carbon nanotubes. The carbon nanotubes produced were characterized by Field Emission Scanning Electron Microscope(FE-SEM), Energy Dispersive x-ray Spectroscopy(EDS), Raman spectroscopy, Thermogravimetric Analysis(TGA)and Transmission Electron Microscope(TEM). A comparison of the morphological profile of the carbon nanotubes produced from these catalysts indicates the catalyst system Fe/Ni/Al to have produced higher quality carbon nanotubes than the catalyst system Co/Zn/Al.

Download Full-text

Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

Polymers ◽

10.3390/polym11081294 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1294 ◽

Cited By ~ 1

Author(s):

Xiaoting Li ◽

Wenxia Jia ◽

Beibei Dong ◽

Huan Yuan ◽

Fengmei Su ◽

...

Keyword(s):

Carbon Nanotubes ◽

Isotactic Polypropylene ◽

Mechanical Tests ◽

High Yield ◽

Scanning Calorimetry ◽

X Ray ◽

Polypropylene Composites ◽

Pressurization Rate ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

Isotactic polypropylene filled with 1 wt.% multi-walled carbon nanotubes (iPP/MWCNTs) were prepared, and their crystallization behavior induced by pressurizing to 2.0 GPa with adjustable rates from 2.5 to 1.3 × 104 MPa/s was studied. The obtained samples were characterized by combining wide angle X-ray diffraction, small angle X-ray scattering, differential scanning calorimetry, transmission electron microscopy and atomic force microscopy techniques. It was found that pressurization is a simple way to prepare iPP/MWCNTs composites in mesophase, γ-phase, or their blends. Two threshold pressurization rates marked as R1 and R2 were identified, while R1 corresponds to the onset of mesomorphic iPP formation. When the pressurization rate is lower than R1 only γ-phase generates, with its increasing mesophase begins to generate and coexist with γ-phase, and if it exceeds R2 only mesophase can generate. When iPP/MWCNTs crystallized in γ-phase, compared with the neat iPP, the existence of MWCNTs can promote the nucleation of γ-phase, leading to the formation of γ-crystal with thicker lamellae. If iPP/MWCNTs solidified in mesophase, MWCNTs can decrease the growth rate of the nodular structure, leading to the formation of mesophase with smaller nodular domains (about 9.4 nm). Mechanical tests reveal that, γ-iPP/MWCNTs composites prepared by slow pressurization display high Young’s modulus, high yield strength and high elongation at break, and meso-iPP/MWCNTs samples have excellent deformability because of the existence of nodular morphology. In this sense, the pressurization method is proved to be an efficient approach to regulate the crystalline structure and the properties of iPP/MWCNTs composites.

Download Full-text

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109884 ◽

1978 ◽

Vol 36 (1) ◽

pp. 548-549 ◽

Cited By ~ 2

Author(s):

N. J. Zaluzec

Keyword(s):

Solid Angle ◽

Analytical Electron Microscopy ◽

Incident Beam ◽

Thin Foil ◽

Experimental Conditions ◽

X Ray ◽

Microchemical Analysis ◽

Analytical Electron ◽

Image Position ◽

Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

Download Full-text

Nanotechnologies. Characterization of single-wall carbon nanotubes using scanning electron microscopy and energy dispersive X-ray spectrometry analysis

10.3403/30175301u ◽

2015 ◽

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Scanning Electron Microscopy ◽

Energy Dispersive ◽

Single Wall Carbon Nanotubes ◽

Single Wall Carbon ◽

X Ray ◽

Spectrometry Analysis ◽

Scanning Electron

Download Full-text

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

Current Analytical Chemistry ◽

10.2174/1573411015666191029152332 ◽

2020 ◽

Vol 16 (7) ◽

pp. 905-913

Author(s):

Youyuan Peng ◽

Qingshan Miao

Keyword(s):

Carbon Nanotubes ◽

Gold Nanoparticles ◽

Ascorbic Acid ◽

Multiwalled Carbon Nanotubes ◽

Ph Value ◽

Biological Fluids ◽

Water Soluble ◽

Multiwalled Carbon ◽

Experimental Conditions ◽

Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Download Full-text

Microwave-assisted Synthesis of Benzoxazoles Derivatives

Current Microwave Chemistry ◽

10.2174/2213335607999200518094114 ◽

2020 ◽

Vol 7 (3) ◽

pp. 183-195

Author(s):

Musa Özil ◽

Emre Menteşe

Keyword(s):

Microwave Irradiation ◽

Reaction Medium ◽

Pharmaceutical Chemistry ◽

Conventional Heating ◽

High Yield ◽

Microwave Assisted Synthesis ◽

Microwave Assisted ◽

Optical Brighteners ◽

Chemistry Research ◽

Extensive Class

Background: Benzoxazole, containing a 1,3-oxazole system fused with a benzene ring, has a profound effect on medicinal chemistry research owing to its important pharmacological activities. On the other hand, the benzoxazole derivative has exhibited important properties in material science. Especially in recent years, microwave-assisted synthesis is a technique that can be used to increase diversity and quick research in modern chemistry. The utilization of microwave irradiation is beneficial for the synthesis of benzoxazole in recent years. In this focused review, we provide a metaanalysis of studies on benzoxazole in different reaction conditions, catalysts, and starting materials by microwave technique so far, which is different from conventional heating. Methods: Synthesis of different kind of benzoxazole derivatives have been carried out by microwave irradiation. The most used method to obtain benzoxazoles is the condensation of 2-aminophenol or its derivatives with aldehydes, carboxylic acids, nitriles, isocyanates, and aliphatic amines. Results: Benzoxazole system and its derivatives have exhibited a broad range of pharmacological properties. Thus, many scientists have remarked on the importance of the synthesis of different benzoxazole derivatives. Conventional heating is a relatively inefficient and slow method to convey energy in orientation to the reaction medium. However, the microwave-assisted heating technique is a more effective interior heating by straight coupling of microwave energy with the molecules. Conclusion: In this review, different studies were presented on the recent details accessible in the microwave- assisted techniques on the synthesis of the benzoxazole ring. It presents all examples of such compounds that have been reported from 1996 to the present. Benzoxazoles showed an extensive class of chemical substances not only in pharmaceutical chemistry but also in dyestuff, polymer industries, agrochemical, and optical brighteners. Thus the development of fast and efficient achievement of benzoxazoles with a diversity of substituents in high yield is getting more noteworthy. As shown in this review, microwave-assisted synthesis of benzoxazoles is a very effective and useful technique.

Download Full-text

Hydrolytic products of Fe(III) after oxidation of Fe(II) by chlorate

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19821069 ◽

1982 ◽

Vol 47 (4) ◽

pp. 1069-1077 ◽

Cited By ~ 1

Author(s):

Karel Mádlo ◽

František Hanousek ◽

Antonín Petřina ◽

Jaroslav Tláskal

Keyword(s):

Electron Microscopy ◽

Ir Spectroscopy ◽

Chemical Analysis ◽

Ferrous Sulphate ◽

Reaction Medium ◽

Potassium Chlorate ◽

X Ray Diffraction ◽

X Ray

Ferrous sulphate was oxidized by potassium chlorate in the pH region 2-7 and at temperatures ranging from 298.1 to 323.1 K and various hydrolytic products of Fe(III) were separated and indentified. The separated solid ferric products were analyzed using a combination of the chemical analysis, IR spectroscopy, X-ray diffraction, and electron microscopy. The following substances were found as major components of the products: Fe2O3.n H2O ("ferric gel"), Fe2O3.n H2O with bound SO2-4 ions ("sulphogel"), α-FeO(OH), γ-FeO(OH) and Fe3O4. Their amount depends particularly on the pH temperature of the reaction medium.

Download Full-text

Ten-Vertex Polyhedral Monocarbaborane Chemistry. The Novel High-Yield Formation of the Ten-Vertex closo Compound [6-(PMe2Ph)-closo-1-CB9H9] from the Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11]

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19932924 ◽

1993 ◽

Vol 58 (12) ◽

pp. 2924-2935 ◽

Cited By ~ 8

Author(s):

Jane H. Jones ◽

Bohumil Štíbr ◽

John D. Kennedy ◽

Mark Thornton-Pett

Keyword(s):

Nmr Spectroscopy ◽

Diffraction Analysis ◽

High Yield ◽

Monoclinic Space Group ◽

The Novel ◽

X Ray Diffraction ◽

Metal Centre ◽

X Ray ◽

Yield Formation ◽

Boiling Toluene

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.

Download Full-text