Graphene functionalizing irradiation

Functionalization of CNTs is of special importance for diverse applications as it can lead not only to the improvement of their solubility but also to their ability to be coupled with other materials creating composites with fascinating characteristics (Hirsch 2002). Irradiation-mduced defects normally increase the reactivity of nanotubes at the surface. Thus, functional groups can be attached to both graphene and nanotubes in spedlic areas (Guo et al. 2005 Salah et al. 2009 Fedoseeva et al. 2010). The induced defects in the jjp -bonded carbon systems due to focused electron and ion beams are governed by the knock-on displacement of carbon atoms, creating vacancies and interstitials in the nanotubes (Krasheninnikov and Nordlund 2010). 

Economopoulos SP, Rotas G, Miyata Y, Shinohara H, Tagmatarchis N (2010) Exfoliation and chemical modification using microwave irradiation affording highly functionalized graphene. ACS Nano 4 7499-7507... 

The photochemical reduction has also been applied for synthesis of graphene-metal NPs. In this case, graphene-metal NPs nanocomposites were prepared by the irradiant white light instead of the chemical reducing agent In one report noble metal salts adsorbed on ultrasonication exfoliated graphene flakes, which were functionalized with ionic surfactants, were reduced... 

As both symmetrical and unsymmetrical stilbenes can be readily synthesized by employing Wittig [126], Heck [127], or McMurry [128] reactions, various graphene-type molecules have been prepared via photolytic cyclodehydrogenation, some of which will be discussed at this point A typical example of photocyclization is the irradiation of the [2.2.2]paracydo-phane 96 in the presence of an oxidant, such as iodine, leading to the corresponding coronene derivatives 97 in high yield. This offers a versatile method for the preparation of new coronene derivatives with different functionality and substitutional symmetry (Scheme 13.26) [129]. 

Figure 5.10 (Left) Schematic representation of PEG functionalization on nano-graphene sheet (NGS) through carboxylic group and subsequent label by Cy7 fluorescence marker. (Right) Photos of tumors on mice after various treatments indicated. The laser-irradiated tumor on the NGS injected mice was completely destroyed. Reproduced with permission from [179].

Zinc 5,10,15,20-tetrakis(4-pyridyl)porphyrin was used to functionalize graphene quantum dots [108]. The nanocomposite was efficient in photocatalyz-ing degradation of methylene blue upon visible-light irradiation. Moreover, the nanomaterial could be recovered and reused with no variance of degradation rate. Therefore, it can be used as visible light-driven photocatalyst to decompose organic pollutants soluble in water. 

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