RTG 2

New Materials/Nanostructures

Jiří Pinkas (CEITEC), Ralph Spolenak (ETH), Reshef Tenne (WIS)

Nanostructured materials are in the focus of academic and industrial research due to their fundamentally new properties and potential applications. We concentrate on chemical synthesis of nanostructures in two areas. One of our goals is the preparation of nanofibers of metals, metal oxides, and metal chalcogenides. We use a multistep process involving electrospinning, calcination, and reduction or sulfidation steps. Our effort is directed toward finding suitable precursors for desired fiber chemical composition, optimization of electrospinnig solution properties and process parameters. Finally, the chemical transformation of nanofibers in different reactive atmospheres led to production of W, W18O49, UO2 ThO2, and WS2 nanofibers. Characterization of the intermediate and final fibers is performed by the XRD, SEM, TEM, HAADF STEM EDS, elemental analyses ICP-OES, and IR spectroscopy methods. In the second area we synthesize solid-solution, Janus, or core-shell metal nanoparticles by the solvothermal hot injection method form suitable molecular precursors and characterize them as for their morphology, composition, shape, and size by XRD, DLS, SAXS, TEM, and STEM-EDS. The aim of our research is to measure by differential scanning calorimetry (DSC) their melting points and compare these values with the calculated melting point depression (MPD) in the corresponding nanoalloy phase diagrams modeled by the CALPHAD method.