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In addition to the control of size, shape and functionalization also the assembly and arrangement of metal nanoparticles come into the focus of materials scientists. This is due to the creation of a variety of properties by the interaction and linkage of a large number of nanoobjects. For building up of complex structures and usable devices several techniques such as the employment of templates and lithography as well as the directed self assembly of nanoparticles are available. Here we show a new method for the preparation of networked structures which is based on the controlled destabilization of noble metal nanoparticles in order to create macroscopic, spongelike, extremely light and highly porous materials which show structuring on the nanometer scale. The fusion of the initial nanoparticles leads to a complex and self-supporting network which forms a monolith with several millimeters in diameter. These materials are formed in liquid media and supercritical drying is used to transform them into aerogels. Several methods such as optical and electron microscopy (SEM, TEM), XPS, nitrogen and hydrogen adsorption etc. were used to unravel important characteristics of the materials created. The related list of promising application fields is wide-ranging: heterogeneous- and electrocatalysis, energy harvesting systems, optical sensors, SERS substrates, broad band optical limiters, thermoelectrics, and conducting transparent substrates. Hence, future work focuses on the characterization and modulation of these materials in order to realize efficient applications and devices. |
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