Synthesis of noble metal nanoparticles and their non-ordered superstructures.

This article highlights our recent work concerning the synthesis of metal nanoparticles and their non-ordered superstructures. After a short introduction, the basic synthetic procedures are explained for the nanoparticles used for the assemblies. Furthermore, a fabrication method is itemized for very monodisperse platinum nanoparticles in aqueous solution ranging in diameter from 10 to 100 nm showing distinct optical properties. The next section deals with the synthesis of non-ordered hydro- and aerogels from the as-prepared sols. Very light large surface materials from gold, silver, platinum and gold-silver and platinum-silver sols can be fabricated with the given method. Another way to ultralight superstructures of noble metal nanoparticles using fungi as templates is described in the third section. Although fungi grow inside the colloidal solutions they can assemble the nanoparticles onto their surfaces. These hybrid systems are thus extremely interesting supported superstructures for applications in heterogeneous catalysis, since the numbers of nanoparticles on the fungus can easily be tuned, and the fabrication process is cost-effective, environmentally friendly and the organic templates can be easily removed by simple combustion for regaining the noble metal.