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Abstract

The goal of this thesis was the development of a synthetic route to stabilizer-free, aqueous iridium oxide colloids. The first part deals with investigations on the preparation and characterization of the newly synthesized iridium oxide nanoparticles in the absence of any stabilizer.
In the second part, the new developed method is extended on the synthesis of the colloidal aqueous bimetallic oxides iridium-ruthenium oxide, iridium-platinum oxide and iridium-osmium oxide with different metal ratios. The newly prepared colloids are characterized extensively via TEM/HRTEM and XPS.
The third part describes the preparation of Ti/IrO₂ electrodes with the newly prepared iridium oxide colloids. This method and the nature of the aqueous, stabilizer-free colloids offers several advantages in contrast to traditional preparation routines. The electrodes are characterized via SEM-technique. Furthermore, they are used as electrodes in the electrochemical oxygen evolution reaction (OER) and the chlorine evolution reaction (CER), investigated by cyclic voltammetry.
The final chapter deals with the photocatalytic water oxidation reaction, using the newly prepared iridium oxide and bimetallic oxide colloids. By irradiation of water with visible light in the presence of the colloids and a photosensitizer, oxygen evolution is observed. The results are compared with literature systems.