Review Article: Hybrid Materials Based on Carbon Nanotubes (original) (raw)
Related papers
Complex carbon nanotube-inorganic hybrid materials as next-generation photocatalysts
Chemical Physics Letters, 2010
Hybridizing carbon nanotubes with complex inorganic nanostructures provides a new route to designing next-generation photocatalysts. These hybrids utilize charge transfer processes through the interface, which reduce the electron-hole recombination rate in the photocatalyst. This work presents the first complex CNT hybrid, using titanium-silicate (TS-1), with dramatically improved photocatalytic activity for the degradation of organic compounds compared with the corresponding nanocomposite and the individual components.
Meta- and hybrid-CNTs: A clue for the future development of carbon nanotubes
Materials Science and Engineering: C, 2007
A new generation of carbon nanotubes (CNTs), which may be named "meta-nanotubes", is more and more the focus of the research worldwide. They result from the transformation of "regular" CNTs by various ways such as functionalisation, doping, substitution, etc. The new nanomaterials thereby created are likely to exhibit new behaviors, specifically regarding properties that pristine CNTs do not possess (reactivity, solubility, magnetism…). The paper includes the description of the various routes to synthesize hybrid CNTs and their related advantages and limitations, while providing examples of the resulting materials from both literature and author's team work. Hybrid SWNTs (abbreviated as X@SWNTs) are one example of meta-nanotubes, and consist in SWNTs whose the hollow core is fully or partially filled with foreign atoms, molecules, or compounds. The inserted material may then exhibit a peculiar behavior with respect to the macroscopic state, for several non-exclusive reasons: 1D-dimension preventing electron scattering and enhancing the role of surface atoms, protection from surface adsorption of disturbing molecules by the carbon sheath, anisotropic lattice distortion or creation of new structures due to imposed dimensions, interactions/electron coupling with the surrounding carbon lattice. A wide field is thus open, possibly even wider than for pristine SWNTs.
Scientific Paper (1-11) PRODUCTION, CHARACTERIZATION AND APPLICATION OF CARBON NANOTUBES (CNTs)
The subject of this study is production of carbon nanotubes using electrolysis in molten lithium chloride and their further characterization and application. The applied electrolytic method for CNTs production using LiCl as electrolyte, commercial graphite (EC4 and EC17) as electrode material at constant cathodic potential, has shown as very suitable and promising. The electrolysis process was investigated by means of cyclic voltammetry, where characteristic peaks of intercalation were detected as a mechanism of CNTs formation. Produced nanoscaled carbon material, including multiwalled carbon nanotubes (MWCNTs) and fullerenes, was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA/DTA) and Raman spectroscopy. Further MWCNTs were used as a support material for preparation of complex electrocatalysts for hydrogen evolution based on non-platinum components. The effects of using MWCNTs instead of traditional carbon blacks as Vulcan XC-72 was studied, by determining the changes in catalyst's structure and activity for hydrogen evolution (polarization characteristics at reference current density). It was found that MWCNTs significantly improve the activity of related catalysts by i) increasing their surface area, ii) improving the electrical conductivity of electrode as a whole and iii) improving the dispersion of active catalytic centers over the electrode surface.
Diamond and Related Materials, 2011
Nanotubes-based nanocomposites to be used as polymer reinforcing/flame-retardant additives are synthesized by decomposition of isobutane at 600°C. Catalytic chemical vapor deposition (CCVD) is carried out over 17 wt%Fe-catalysts supported on various oxides (Al 2 O 3 , MgO, CaO, SrO or BaO) reduced at 600°C. Catalysts utilized and carbonaceous deposits obtained are systematically characterized by the use of several analysis techniques, in order to investigate the influence of catalyst specifics on reaction yield, selectivity and characteristics (crystallinity and purity) of the grown nanotubes. The results show that the support greatly influences the catalyst performance. The lack of metallic iron renders Fe/SrO-and Fe/BaO-catalysts inactive. Fe/Al 2 O 3 catalysts exhibit the highest catalytic activity, but give rise to scarce selectivity and large metallic impurity contents. Contrarily, using Fe/MgO and Fe/CaO catalysts leads to lower yields, but allows reducing impurities and remarkably improving selectivity and nanotube crystallinity.
Synthesis and characterization of hybrid composites based on carbon nanotubes
Electrochimica Acta, 2009
Multi-wall carbon nanotubes (CNTs) were coated with protonated polyaniline (PAni) in situ during the chemical polymerization of aniline. Uniform coating of CNT with PAni was observed by scanning electronic microscopy. An improvement in the covering of CNT composites was found by the association of poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT). The conductivity of composites has been compared with the conductivity of the PAni and CNT. A maximum conductivity of 96.8 S cm −1 has been found for a PAni/PDMcT/CNT composite. High capacitance value (289.4 F g −1 ) was also determined for this composite, indicating that all materials, PAni, PDMcT and CNT, remain active during the charge-discharge cycling. The reduction in the capacitance after 100 cycles was found to be less than 25%. The capacitive behavior of all materials was confirmed by impedance analysis.
CARBON NANOTUBES: SYNTHESIS, PROPERTIES AND TECHNOLOGICAL APLLICATIONS
This project reviews synthesis, properties and technological applications of carbon nanotubes. The different synthesis methods of carbon nanotubes are illustrated briefly. The energy dependence of density of states was used to determine the optical properties of CNT. Finally, brief description of optical and electronic properties was presented. Using MATLAB Code the theoretical simulation of electronic band structure as a function of wave vector, the band gap as a function of tube diameter and the density of state as a function of energy band are generated.
Carbon nanotubes: synthesis, properties and engineering applications
Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp 2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.
Hybridization of natural inorganic materials (natural minerals) by carbon nanotubes
2018
In this work we briefly summarized results of extensive experiments focused on hybridization natural inorganic substrates by carbon nanotubes (CNTs). The kernel of the experiments is catalytic synthesis of CNTs on/into natural inorganic substrates involving two technological processes. The first one is incorporation of catalytically active metals into the structure of the substrates while the second one is in-situ synthesis of CNTs in a HF CVD reactor. The main objective of the experiments is to contribute to understanding the mechanism of the rise of new hybrid materials. Selection of the natural inorganic substances includes a group of minerals with similar chemical compositions but with markedly different morphologies as well as materials containing iron - colloid scraps after raw mineral mining. The main methods of characterizing the hybrids are Raman spectroscopy along with scanning and transmission electron microscopies.