Graphene is at the centre of nanotechnology research. In order to fully exploit its outstanding properties, a mass production method is necessary. Two main routes are possible: large-scale growth or large-scale exfoliation. Here, we demonstrate graphene dispersions with concentrations up to ~0.01 mg/ml by dispersion and exfoliation of graphite in organic solvents such as N-methylpyrrolidone. This occurs because the energy required to exfoliate graphene is balanced by the solvent-graphene interaction for solvents whose surface energy matches that of graphene. We confirm the presence of individual graphene sheets with yields of up to 12% by mass, using absorption spectroscopy, transmission electron microscopy and electron diffraction. The absence of defects or oxides is confirmed by X-ray photoelectron, infra-red and Raman spectroscopies. We can produce conductive, semi-transparent films and conductive composites. Solution processing of graphene opens up a whole range of potential large-scale applications from device or sensor fabrication to liquid phase chemistry. Hernandez et al 2Graphene is one of the most exciting nano-materials due to the cascade of unique physical properties that have recently been demonstrated. For example, due to the details of its electronic structure, charge carriers in graphene behave as massless Dirac fermions 1 . Furthermore, novel effects such as an ambipolar field effect 2 , room temperature quantum Hall effect 3 , breakdown of the Born-Oppenheimer approximation 4 are observed. However, as was the case in the early days of nanotube and nanowire research, graphene at present still suffers from one problem, critical for its mass-scale exploitation: it cannot yet be made with high yield. The standard procedure used to make graphene is micromechanical cleavage 5 . This yields the best samples to date, with mobilities up to 200,000 cm 2 /Vs. 6 However, single layers are a negligible fraction amongst large quantities of thin graphite flakes. Furthermore, it is difficult to see how to scale up this process to mass production. Alternatively, growth of graphene is also commonly achieved by annealing SiC substrates, but these samples are in fact composed of a multitude of domains, most of them sub-micrometer, and not spatially uniform in number, or in size over larger length scales 7 . A number of works have also reported graphene growth on metal substrates 8,9 , but this would require the sample transfer to insulating substrates in order to make useful devices, either via mechanical transfer or, via solution processing.Recently, a large number of papers have described the dispersion and exfoliation of graphene oxide (GO) [10][11][12][13] . This material consists of graphene-like sheets, chemically functionalised with compounds such as hydroxyls and epoxides, which stabilise the sheets in water 14 . However, this functionalisation results in considerable disruption of the electronic structure of the graphene. In fact GO is an insulator 15 rather than a semi-metal and is conceptually differen...

Recently, milligram quantities of MoS2 fullerene-like nanotubes and negative curvature polyhedra (generically called inorganic fullerene-like material, IF), were reproducibly obtained by a gas phase reaction from an oxide precursor (Feldman, Y.; Wasserman, E.; Srolovitz, D. J.; Tenne, R. Science 1995, 267, 222. Srolovitz, D. J.; Safran, S. A.; Homyonfer, M.; Tenne, R. Phys. Rev. Lett. 1995, 74, 1778). The present work focuses on the mechanism of the synthesis of IF-MS2 (M = W, Mo). The IF material is obtained from oxide particles smaller than ca. 0.2 μm, while larger oxide particles result in 2H-MS2 platelets. The key step in the reaction mechanism is the formation of a closed layer of MS2, which isolates the nanoparticle from its surroundings and prevents its fusion into larger particles. Subsequently, the oxide core of the nanoparticle is progressively converted into a sulfide nanoparticle with an empty core (IF). Taking advantage of this process, we report here a routine for the fabrication of macroscopic quantities of a pure IF-WS2 phase with a very high yield. As anticipated, the size distribution of the IF material is determined by the size distribution of the oxide precursor. The present synthesis paves the way for a systematic study of these materials which are promising candidates for, e.g., solid lubrication.

Reduced graphene oxide/platinum supported electrocatalysts (Pt/RGO) were synthesized by employing a fast and eco-friendly microwave-assisted polyol process, which facilitated the simultaneous reduction of graphene oxide and formation of Pt nanocrystals. This system was tested for potential use as an anode material through the electrooxidation of methanol. Compared to the commercial carbon-supported Pt electrocatalysts, the Pt/ RGO showed an unprecedented CO poisoning tolerance, high electrochemical active surface area, and high catalytic mass activity for methanol oxidation reaction, demonstrated by increases of 110, 134, and 60%, respectively. We found that the high concentration of oxygen functional groups on reduced graphene oxide plays a major role on the removal of carbonaceous species on the adjacent Pt sites, underlining a synergetic effect between the oxygen moieties on graphene support and Pt nanoparticles. The present microwave assisted synthesis of Pt/RGO provides a new path to prepare electrocatalysts with excellent electrocatalytic activity and CO tolerance, which is of great significance in energy-related applications.

The complete crystallography of a one-dimensional crystal of potassium iodide encapsulated within a 1.6-nanometer-diameter single-walled carbon nanotube has been determined with high-resolution transmission electron microscopy. Individual atoms of potassium and iodine within the crystal were identified from a phase image that was reconstructed with a modified focal series restoration approach. The lattice spacings within the crystal are substantially different from those in bulk potassium iodide. This is attributed to the reduced coordination of the surface atoms of the crystal and the close proximity of the van der Waals surface of the confining nanotube.

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Single-walled carbon nanotubes (SWNTs) can be used as templates for the growth of low-dimensional inorganic materials whose structures and properties often differ greatly from those of the bulk. Here we describe the detailed crystallography of an entire helical one-dimensional cobalt diiodide nanostructure encapsulated within a SWNT. This material has an unprecedented twisted double tetrahedral chain structure arising from a rotation of Co(2)I(4) units along its length. The complete nanostructure comprises two distinct regions with oppositely handed helices separated by a short disordered region. The encapsulating SWNT shows a commensurate ovoid distortion reflecting an unexpectedly strong interaction between the nanostructure and the SWNT.