"Heterogeneous catalysis is an area where nanotechnology is present in people's everyday lives. Catalytic processes are found in diverse applications such as fuel-refining, the petrochemical industry, fertiliser production, automotive catalytic converters, biochemistry etc. They also provide a pathway to renewable, clean energy in the form of hydrogen fuel cell technology. Most modern catalysts take the form of catalytically active nanoparticles dispersed over some highly porous support medium. It is expected that the activity of these particles is largely determined by the density of catalytically active sites on the particle surface. The proposed research will establish a new methodology in nanocatalyst research by using high-resolution experimental techniques to establish a close and unambiguous correlation between the morphology and reactivity of individual nanoparticles. The principal tools will be scanning tunneling microscopy (STM), which offers atomic-scale structural resolution, combined with scanning Auger microscopy (SAM), offering nanometer-scale chemical information. These techniques will be used to measure the surface structure and composition of catalytic nanoparticles before, after and perhaps even during a reaction and to correlate this data with the reactivity of the nanoparticles measured by temperature programmed desorption (TPD). By measuring the surface structure of individual nanoparticles it will then be possible to make a direct comparison with the results of computational modeling. This will open the possibility to optimize the nanoparticle size and shape in order to maximize the number of catalytically active surface sites, while minimizing the unused volume, thereby improving the efficiency of the catalyst while reducing the material cost."