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Molybdenum carbides have been prepared by the temperature programmed reaction method using mixtures of hydrogen and methane, hydrogen and ethane, and hydrogen and butane, and characterised with X-ray diffraction, transmission electron microscopy, 13C solid state NMR and EXAFS spectroscopy. The results show that the choice of hydrocarbon used to synthesise molybdenum carbide significantly affects the structure and texture of the resultant materials. Increasing the chain length of the carburising agent reduces the particle size and the temperature for complete phase transformation from molybdenum oxide to carbide is lowered. Carburising with a mixture of hydrogen and methane gives rise to hexagonal closed packed (hcp) carbide, while when using butane as the carbon source, molybdenum oxide is mainly reduced to face centred cubic (fcc) carbide. However, using ethane as the carbon source, the resultant carbide has a mixed phase composition with the hcp phase predominant. The molybdenum carbide prepared with ethane as the carbon source has the roughest surface and highest hydrogen adsorption capacity, while that prepared with butane has a very condensed surface. There is a substantial difference in the molybdenum co-ordination environments present among the carbides prepared with different carburising agents.

The filling of carbon nanotubes with metals and metal oxidesvia one- and two-step processes is presented. Both molten media and wet chemistry solution methods have been used to introduce foreign materials into the hollow nanotube cavities. Chemical reactions inside the tubes have been carried out, including the reduction of encapsulated materials to the metals. The nature of the crystalline filling has been found to be highly dependent on the techniques used. Wet chemical methods tend to result in filling which consists of discrete crystallites, whereas molten media methods tend to give long, continuous single crystals.

A systematic study on the effect of varying a number of experimental parameters including temperature, solvent and concentration on the nature of C60 crystalline structures (fullerites) grown using the liquid–liquid precipitation method is reported. A variety of fullerite structures of varying degrees of quality are obtained depending on the conditions used. We present evidence of a solvent dependent annealing effect leading to an improvement in fullerite quality. Variation of the alcohol C60 solubility is seen to generally lead to an increase in the size of the fullerite rods obtained which may also be related to the relative polarity of the solvents used. It was observed that aromatic solvents containing electron withdrawing groups tended to destabilise fullerite rod growth. We report the smallest repeatable pristine single crystal fullerite rods grown with diameters of ∼80 nm, representing close to an order of magnitude decrease in scale compared to other structures obtained using this method. The growth of these structures raises questions regarding the currently assumed method of growth based on C60 colloid formation. The new class of small fullerites obtained are characterised for their structural, physical and optical properties.

High purity single crystal C60 rods with uniform dimensions are synthesized by a rapid and facile approach which can be completed over a timescale of typically a few minutes. The morphology of the fullerene product has been characterized in detail by scanning electron microscopy, scanning transmission electron microscopy, and atomic force microscopy, demonstrating that the resulting materials are solid, hexagonal cross-sectioned rods with novel faceted tips. High resolution transmission electron microscopy investigations reveal that the rods are face-centered cubic packed single crystals. Vibrational and electronic spectroscopy studies provide compelling evidence that the rods are a van der Waals solid since the electronic structure of the component C60 molecules is largely preserved. The structures obtained are found to possess novel optoelectronic properties exhibiting low energy absorption not reported in related structures and materials to date. Furthermore significant room temperature photoluminescence is obtained from the C60 rods accompanied by a small blue shift of the spectra which is also observed for the first ‘allowed’ absorption transitions. Given their rapid synthesis, excellent purity, optical and charge transport properties these fullerene structures are expected to be a promising materials for nanoelectronic devices including thin film organic solar cells and photodetectors.