Nanomaterials carbonaceous materials

The recent discovery that fullerene-related nanomaterials are formed under electrolytic conditions [14, 15] adds further technical and fundamental perspectives to the nanotube field. Using graphite electrodes immersed in molten LiCl under argon, nanotube production can be improved significantly. Depending upon the conditions, some 20-30% of the carbonaceous material formed may consist of graphitic nanotubes. Under other conditions quite different material is produced. 

The strategy based on the assembly of conducting carbraiaceous nanomaterials to sepiolite and palygorskite is based on two approaches (1) the development of carbonaceous materials from organic precursors adsorbed on the fibrous clays, and (2) the direct assembly of carbon nanotubes with the fibrous clays. 

Figure 4.11.28 shows the DTG curves for various carbonaceous materials, carbon nanotubes and carbon fibers, active charcoal, and graphite. Obviously, the nanotubes have the highest reactivity, followed by nanofibers, active charcoal, and graphite. It can also be seen that the nanomaterials are quite pure (ideal shape of the DTG signal), whereas a fraction of the charcoal is less reactive than the fraction that reacts first. 

Electrochemical biosensor performance such as sensitivity, protein stability, selectivity or reproducibility have been improved due to the use of different carbonaceous materials and combination of them. To improve the sensitivity of a electrochemical biosensor is necessaiy to increase the enzyme amount in a proper immobilization manner. CNTs are good candidates and in this regard, some authors combine carbon nanomaterials with conducting polymers, which gives rise the biosensor special properties due to the synergic effect of the individual components. The electrochemical determination of lactate by the use of lactate oxidase (LOx) based SPE platform takes advantages of the combination of MW-CNT and conductive polysulfone polymer, and such an electrochemical biosensor was successfully applied for the quantification of lactate in wine and beer. In some cases, the inconvenient is the low stability associated with the deleterious interaction of the enzyme LOx with the composite CNT/polymer substrate. 

A febrication procedure of bulk electrodes was first proposed by Lev s group [19] and was subsequently widely employed for the development of carbon ceramic electrodes. The common feature of these electrodes is the high content of carbonaceous materials. Generally, a sol is first mixed thoroughly with the desired amount of the carbon-based material. Then, the mixture is packed into one end of a plastic body that includes a stainless steel wire as an electrical contact (Figure 46.5). After sol condensation, polymerization, and gel drying, the resulting electrodes are polished to yield a smooth surface required for electrochemical measurements. In this setup, the sol-gel material, with or without nanomaterials, serves as a binder for the carbon-based conductive material. 

To overcome the problems coimected to the isolation and recovery of such tiny particles from the reaction mixture, they are combined with magnetic nanomaterials and separated using external magnets. Literature already reported several protocols for preparing a wide variety of catalytic magnetic nanomaterials from carbonaceous to metal oxide- and polymer-derived magnetic materials [25]. 

We anticipate that this chapter would trigger more research efforts towards finding other innovative means to render them more robust as coatings, as these carbonaceous films can be made easily in large quantities and are much less expensive than other nano-structured carbon materials. Potential future directions could be, for instance, synthesis of polymer-carbon nanocomposite surfaces made up of carbon nanotubes, graphene or other carbon nanomaterials as well as flame synthesis of other soft materials which can be thermally triggered to crosslink or polymerize during nanoparticle network deposition. 

With the surge in research on carbonaceous nanomaterials, the combination of these entities with metal oxide nanoparticles is enticing as the electronic properties of materials such as graphene may influence particle characteristics. For this reason, the interaction of titania nanoparticles with B- and N-doped graphene has been investigated recently in order to study the photodegradation of dye molecules by these composites. Anatase Ti02... 

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