Solid catalysts are often structured on the nanoscale. Various methods are available to achieve such nanostructuring, including different templating pathways. The combination of high surface area support materials and pre-formed nanoparticles provides a highly flexible access to nanostructured catalysts. We use a wide range of different nanoparticles to synthesize high activity supported catalysts, for instance for ultra-low temperature CO oxidation. Elaborate procedures are used for the synthesis of core-shell systems, in which single metal nanoparticles are encapsulated in hollow spheres. Since the nanoparticles are effectively isolated from each other, sintering is effectively prevented.