Stoichoimetric graphene fluoride monolayers are obtained in a single step by the liquid-phase exfoliation of graphite fluoride with sulfolane. Comparative quantum-mechanical calculations reveal that graphene fluoride is the most thermodynamically stable of five studied hypothetical graphene derivatives; graphane, graphene fluoride, bromide, chloride, and iodide. The graphene fluoride is transformed into graphene via graphene iodide, a spontaneously decomposing intermediate. The calculated bandgaps of graphene halides vary from zero for graphene bromide to 3.1 eV for graphene fluoride. It is possible to design the electronic properties of such two-dimensional crystals.

Graphene sheets derived from dispersion of graphite in pyridine were functionalised by the 1,3 dipolar cycloaddition of azomethine ylide. The organically modified graphene sheets are easily dispersible in polar organic solvents and water, and they are extensively characterised using several spectroscopic and microscopy techniques.

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The intercalation of sugar in smectite clays and the resulting clay−carbon composites after thermal treatment in Ar are described. Sugar activation by H2SO4 treatment affords novel clay−carbon composites in which the layer structure of clay is preserved. Combined XRD and TEM measurements strongly suggest that carbonization at 600 °C leads to graphenes distributed over the clay surfaces, forming a nanometric carbonaceous film. Thermal analysis and XRD results show enhanced thermal stability of the clay−carbon composites with the mineral preserving its layered structure even at 900 °C. Acid demineralization of the clay substrate yields novel carbonaceous materials of high surface areas. The templating role of clay substrate in the growth of the carbonaceous layer is revealed by HRTEM micrographs, which show limited packing of graphenes accompanied by improved surface areas. The present clay−carbon composites are low-temperature-synthesized absorbents without the need of high-temperature activation.

Considerable progress has been made recently in the use of nanoporous materials for hydrogen storage. In this article, the current status of the field and future challenges are discussed, ranging from important open fundamental questions, such as the density and volume of the adsorbed phase and its relationship to overall storage capacity, to the development of new functional materials and complete storage system design. With regard to fundamentals, the use of neutron scattering to study adsorbed H 2 , suitable adsorption isotherm equations, and the accurate computational modelling and simulation of H 2 adsorption are discussed. The new materials covered include flexible metal-organic frameworks, core-shell materials, and porous organic cage compounds. The article concludes with a discussion of the experimental investigation of real adsorptive hydrogen storage tanks, the improvement in the thermal conductivity of storage beds, and new storage system concepts and designs.