... is of large interest in the field of Electrocatalysis. In this project, nanoparticles with controlled  chemical composition, particle size and particle shape will be synthesized by modern colloidal methods. By tuning the chemical composition, particle shape and particle size, the reactivity, selectivity and durability of metal nanoparticles will be tailored for various electrochemical reactions. The structure of pristine nanoparticles will be characterized by high-resolution transmission electron microscopy and X-ray diffraction methods. Preliminary electrochemical investigations using cyclic voltammetry and RDE technique will be performed to evidence the improvements in activity, selectivity and durability for the corresponding electrochemical reactions.

….have recently emerged as a promising strategy to improve the durability of electrocatalysts. Due to the high anodic potential (up to 1.5 V/RHE) during the start-stop conditions the cathode electrocatalysts strongly suffer from the corrosion of carbon support material (C + 2H₂O → CO₂ + 4H⁺ + 4e^–; E^O = 0.207 V/RHE) associated with particle detachment and dissolution of Pt nanoparticles. Generally, carbon is thermodynamically not stable in the potential regime of oxygen reduction reaction. In this project, various strategies like increase of graphitization, integration of other atoms (N, S) in the carbon framework, surface modification by inserting functional groups will be developed. Afterwards, the modified carbon materials will be used as support materials for Pt nanoparticles and will be electrochemically investigated by RRDE technique.

...are promising candidates for model catalysts. Single molecule spectroscopy, e.g. fluorescence correlation spectroscopy, allows population selective detection of kinetic parameters of single particles. In contrast to single molecule techniques, traditional methods always provide an average information, ignoring possibly differing properties in nanoparticle mixtures. Performing single molecule experiments allows to separate catalytic active and inactive particles within one solution. The fluorescent properties of nanoparticles are very sensitive to size, charge and surface modification of the particles and therefore are excellent reporters for changes of the particles during the catalytic cycle.
The goal of this project is the synthesis of bimetallic fluorescent and ligand-free Au nanoparticles. These nanoparticles will first be characterized by TEM, XPS and fluorescence spectroscopy. Additional single molecule experiments will provide data about the hydrodynamic radius, which is mainly determined by the nanoparticle ligand shell.