CNTs and Graphene

For the successful deposition of platinum nanoparticles on CNT, most deposition methods known previously from the impregnation of carbon supports can be applied [63]. However, in order to achieve a homogeneous distribution of the metallic nanoparticles on all nanotubes, these have to be activated before deposition. Moreover, since they are often entangled, such that the reduction agent 

Inspired by the observation, that binary Pt=Ru nanoparticles supported on CNT showed a promising performance as anode catalysts in PEMFCs, Harris et al. [65] used density functional theory calculations to study the anchoring of the nanoparticles to the nanofibers. They found a strong metal-carbon bond ( 3 eV) with covalent character between the graphene structure and the metal (111) crystal planes, which might be the reason for the higher stability found in these systems. 

Apart from using CNT as stable and high-surface-area supports, they can also be applied as the catalytically active component in fuel cells (see Section 7.3 exclusively). 

For both materials, CNT and graphene, numerous publications demonstrate their applicability as promising support materials in PEM FCs. In lab-scale tests, their higher stability, durability, and activity have been shown manifold. Yet, up to now nobody knows which drawbacks have to be overcome to commercially apply CNTs and graphene on a larger scale in real fuel cell stacks. This, only time will tell. 

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Although there have been great advances in covalent functionalization of fullerenes to obtain surface-modified fullerene derivatives or fullerene polymers, the application of these compounds in composites still remains unexplored, basically because of the low availability of these compounds [132]. However, until now, modified fullerene derivatives have been used to prepare composites with different polymers, including acrylic [133,134] or vinyl polymers [135], polystyrene [136], polyethylene [137], and polyimide [138,139], amongst others. These composite materials have found applications especially in the field of optoelectronics [140] in which the most important applications of the fullerene-polymer composites have been in the field of photovoltaic and optical-limiting materials [141]. The methods to covalently functionalize fullerenes and their application for composites or hybrid materials are very well established and they have set the foundations that later were applied to the covalent functionalization of other carbon nanostructures including CNTs and graphene. 

In the case of MnO/ ( it is known to reduce on the surface of CNTs and graphene spontaneously to produce Mn02 NPs [182,183]. Solvothermal assisted precipitation of metal oxides can occur in milder solutions [184]. For example, mixed metal oxide NPs of CoFe204 have been deposited on GO from metallic salt precursors via the addition of ethanolamine followed by incubation at 180 °C in a sealed vessel [185]. Mixing GO with Cd2+ in DMSO followed by solvothermal treatment has been shown to both reduce GO to RGO and coat with CdS QDs [186]. 

Nanocarbons other than CNTs and graphene often exhibit similar surface chemistry and can be hybridized in a similar fashion. For example, single-walled carbon nanohorns (SWCNHs) have been oxidized via heat treatment in air atmosphere followed by immersion in a solution containing H2PtCl6. The Pt ions adsorbed to the oxidized SWCNHs and were then reduced via addition of sodium citrate to form Pt NPs [150],... 

With t taking experimental values in the range 1-5 for both CNTs and graphene [26,27,28]. The upper limit of equation (8.4) is ct0, which has been experimentally found to be as high as around 104 S/m for both CNTs [24] and graphene [29]. These values can be taken as indicators of the maximum conductivities attainable by dispersing nanocarbons in polymer matrices. 

The analysis of the shape, intensity, and shift of these Raman bands allows evaluating the electronic state, structural deformation, and defect density in CNTs and graphene. When complemented by other high-resolution microscopy techniques such as atomic force microscopy (AFM) or X-ray diffraction, pRS offers valuable insight into the structure and properties of these low-dimensional carbon systems. 

For further evolution of the probe nanotechnology we should have new types of fine probes. We have developed focused ion beam (FIB) methods for silicon probe modification and sharp pointing. They are very powerful for the fabrication of probes with desirable properties and orientations. Fig. 3 displays the application of this method for integrated CNT and graphene based electronics and nanosystems in mass production. 

In recent years, carbon nanotubes (CNTs) and graphene have been extensively studied due to their outstanding electron mobility, mechanical strength and large specific surface area [1]. These properties make them attractive in a wide variety of applications ranging from sensors and actuators [2], catalysts [3], batteries... 

In addition to small molecules, carbon materials such as carbon nanotubes (CNTs) and graphene oxides (GO) also exhibit the ability to tune the structure of typical helical DNA and non-canonical DNA structures due to their unique structural, chemical, and physical properties. Thus, their interactions... 

The addition of a conductive secondary component can improve not only the CPs anticorrosion properties but also their electroactivity, by facilitating charge-transfer processes between the two components [60-66]. As conductive components, carbon-based nanostructures are the most used, such as carbon nanotubes (CNTs) and graphene. CNTs were introduced in PANI [60-68], PPy [69], PoPD [70]. It has to be highlighted the functionalisation of CNTs plays an important role in the preparation... 

As summarized in Table 10.1, NDs, CNTs and graphene have different properties related to their structural arrangement. Due to their features, these carbon nanostructures have attracted a wide variety of research dedicated to the synthesis, functionalization and future applications of them, where the use of these nanomaterials as reinforcement of polymers... 

Tailoring the properties of polymers with the inclusion of nanometric carbon depends on many factors. Among them, the parameters most taken into account are (a) the size, structure and distribution of the nanofiller in the matrix and (b) the interface between the nanofillers and the matrix. This chapter focuses mainly on the effects that functionalization and concentration of nanofillers have in the storage modulus and tribological properties of polymer nanocomposites reinforced with NDs, CNTs and graphene, describing briefly the hardness and scratching performance achieved in these nanocomposites. 

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