Evaluating the characteristics of multiwall carbon nanotubes

Lehman, John H.; Terrones, Mauricio; Mansfield, Elisabeth; Hurst, Katherine E.; Meunier, Vincent

doi:10.1016/j.carbon.2011.03.028

Cited by 1,006 publications

(611 citation statements)

References 104 publications

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“…22,42 The peak at 3427 cm -1 , which appeared in all nanocomposites after addition of titania, is assigned to carbonyl and/or O-H bonds associated with hydroxyl groups. [42][43][44][45] The peak at 2920 cm -1 is assigned to a C-H bond within the MWCNT sample. 46 A low intensity peak at 1103 cm -1 representing Ti-O-C bond assigned to a covalent link between titania and MWCNTs 47 was observed in the nanocomposites produced by both synthetic methods.…”

Section: Functional Groups and Bonding Within Nanocompositesmentioning

confidence: 99%

Multiwalled carbon nanotube-titania nanocomposites: Understanding nano-structural parameters and functionality in dye-sensitized solar cells

Mombeshora¹,

Simoyi²,

Nyamori³

et al. 2015

S.Afr.j.chem

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Nanocomposites consisting of multiwalled carbon nanotubes and titania were synthesized by two methods, namely, sol-gel and chemical vapour deposition (CVD) methods. The work takes advantage of the bridging ability of nanotechnology between macromolecules and the solid state process in engineering alternative nanomaterials for various applications including solar cell fabrication. Physical and chemical characterization of the mesoporous nanocomposites from the two synthetic methods were investigated using Raman spectroscopy, thermogravimetric analysis, Fourier transformation infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, surface characterization and X-ray diffraction analysis. Physicochemical properties in the nanocomposites such as thermal stability, pore volume, crystallinity and surface area were observed to be a subject of MWCNT: titania ratios and synthetic methods. From the CVD synthetic method, observed attributes include more uniform and smoother coating; better crystallinity and larger pore width than sol-gel method. On the other hand, nanocomposites from sol-gel synthetic method had larger surface areas, were more defective and less thermally stable than those from CVD. Nanocomposites by the CVD method performed 39.2 % more efficient than those from sol-gel in light-harvesting experiments. The study shows that the nanocomposites synthesized were more effective than titania alone when the cheaper natural dye, Eosin B, was used. This highlights the great potential of typical nanomaterials in improving the performances of titania in DSSCs as well as lowering the cost of the ultimate devices.

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Section: Functional Groups and Bonding Within Nanocompositesmentioning

confidence: 99%

Multiwalled carbon nanotube-titania nanocomposites: Understanding nano-structural parameters and functionality in dye-sensitized solar cells

Mombeshora¹,

Simoyi²,

Nyamori³

et al. 2015

S.Afr.j.chem

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“…The first is related to disorder structure bond attributed to the defect in the curved graphene sheet and tube ends or even amorphous carbons. The second peak is referred to the structure integrity of sp 2 bonded carbon atoms in two-dimensional hexagonal lattices, indicating the presence of crystalline graphitic carbon [23]. The I D /I G indicates the quality of MWNTs, the higher intensity of I D /I G ratio is reflective of lower quality of MWNTs.…”

Section: Instrumentsmentioning

confidence: 99%

A study on the dependence of structure of multi-walled carbon nanotubes on acid treatment

et al. 2015

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In the current research, the role of both concentrated nitric acid and ultrasound waves on oxidation of multi-walled carbon nanotubes (MWNTs) was studied. The functionalized MWCNTs were characterized by transmission electron microscopy (TEM), thermogravimetric analyzer, and Fourier transform infrared spectroscopy (FTIR) techniques. It was found that desirable modifications to MWNTs occurred after acid treatment. Carboxylic acid groups were appeared on the side surfaces of MWNTs. FTIR presented the formation of oxygen-containing groups such as C=O and COOH after modification by concentrated nitric acid. The TEM images showed that the aspect ratio of opened MWCNTs was controlled by both ultrasonic waves and acid treatment time. It was also found that the exposure of about 4 h in nitric acid led to the highest removal of the impurities with the least destructive effect.

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“…37 The G' band is used as an indication of the purity of CNTs, as coupling two-phonon process does not occur for disordered samples. 38 In this work, the ratio of intensity of the D to G band (I D /I G ), and the ratio of intensity of the G' to G band (I G' /I G ) are used to evaluate the degree of defects (i.e. edge dislocations) 39 and crystallinity of the product CNTs.…”

Section: As Shown Inmentioning

confidence: 99%

Processing Real-World Waste Plastics by Pyrolysis-Reforming for Hydrogen and High-Value Carbon Nanotubes

Nahil

Miskolczi

et al. 2013

Environ. Sci. Technol.

181

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Producing both hydrogen and high-value carbon nanotubes (CNTs) derived from waste plastics is reported here using a pyrolysis-reforming technology comprising a two-stage reaction system, in the presence of steam and a Ni-Mn-Al catalyst. The waste plastics consisted of plastics from a motor oil container (MOC), waste commercial high density polyethylene (HDPE) and regranulated HDPE waste containing polyvinyl chloride (PVC). The results show that hydrogen can be produced from the pyrolysis-reforming process, but also carbon nanotubes are formed on the catalyst. However, the content of 0.3 wt.% polyvinyl chloride in the waste HDPE (HDPE/PVC) has been shown to poison the catalyst and significantly reduce the quantity and purity of CNTs. The presence of sulphur has shown less influence on the production of CNTs in terms of quantity and CNT morphologies. Around 94.4 mmol H 2 g -1 plastic was obtained for the pyrolysis-reforming of HDPE waste in the presence of the Ni-Mn-Al catalyst and steam at a reforming temperature of 800 °C. The addition of steam in the process results in an increase of hydrogen production and reduction of carbon yield; in addition, the defects of CNTs e.g. edge dislocations were found to be increased with the introduction of steam (from Raman analysis).

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Evaluating the characteristics of multiwall carbon nanotubes

Cited by 1,006 publications

References 104 publications

Multiwalled carbon nanotube-titania nanocomposites: Understanding nano-structural parameters and functionality in dye-sensitized solar cells

Multiwalled carbon nanotube-titania nanocomposites: Understanding nano-structural parameters and functionality in dye-sensitized solar cells

A study on the dependence of structure of multi-walled carbon nanotubes on acid treatment

Processing Real-World Waste Plastics by Pyrolysis-Reforming for Hydrogen and High-Value Carbon Nanotubes

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