The present thesis deals with the synthesis and characterization of nanostructured, phase-pure ferrite materials (MFe2O4) concerning their potential use in photocatalysis and photoelectrochemistry. The cubic spinel magnesium and zinc ferrite (MgFe2O4 and ZnFe2O4) and the orthorhombic calcium ferrite (CaFe2O4) were chosen as photocatalyst materials due to their composition of earth-abundant and non-toxic elements. They exhibit band gaps of 1.9 eV 2.0 eV[2,3], which allows to perform photocatalytic reactions under visible light excitation. While MgFe2O4 and CaFe2O4 are reported to be n-type and p-type semiconductors, respectively, contradictory reports were published on the band positions and semiconducting behavior of ZnFe2O4. Thus, this thesis aims to clarify these characteristics for the three chosen compounds.Solution-based synthesis procedures were selected on the basis of literature reports[4,5] to produce nanoparticles and mesoporous thin films of the selected ferrite compounds. For nanoparticle synthesis, a microwave-assisted approach was chosen. Furthermore, methods for post-synthetic and in situ production of colloidal solutions were developed. This offers the possibility to study the interplay of colloidal stability, the nature of surfactants and the resulting efficiency for photocatalytic degradation processes.To create mesoporous thin films, a dip-coating approach was applied investigating different block-copolymers used as porogens. The synthesis procedure was optimized with regard to the activity under visible light. By this means, conclusions on the connection between the pore morphology and crystallinity of mesoporous thin films and their photoelectrochemical performance was possible.Special focus was put on the phase purity of the synthesized ferrites, which was checked not only by X-ray diffraction (XRD), but also by Raman spectroscopy. Besides, various analytical methods such as spectroscopic tools, physisorption, photoelectrochemistry or synchrotron-based X-ray absorption techniques (XES, XANES, RIXS) were employed to achieve a detailed characterization and a deeper understanding of the photocatalytic and photoelectrochemical properties of the chosen ferrite materials.
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