Design of multifunctional prussian blue analogues for solar driven water oxidation ; Güneş ışığını kullanarak suyu yükseltgeyebilen çok işlevli prusya mavisi türevlerinin tasarımı

Cataloged from PDF version of article. ; Thesis (Ph.D.): Bilkent University, Department of Materials Science and Nanotechnology, İhsan Doğramacı Bilkent University, 2021. ; Includes bibliographical references (leaves 159-176). ; The development of earth-abundant, robust, and low-cost photoanodes for water oxidation is one of the most critical steps in ‘artificial leaf’. A promising approach in this field is to build dye-sensitized photoanodes by coupling a molecular photosensitizer (PS) with a water oxidation catalyst (WOC) on a proper semiconductor (SC) for efficient charge separation. All dye-sensitized photoanodes reported in the literature consist of either a ruthenium photosensitizer, a ruthenium water oxidation catalyst, or both. We aim to overcome this critical challenge by developing a new family of organic- or iron-based donor-acceptor chromophores incorporated in a Prussian blue (PB) structure, which are coated on proper semiconductors. Our studies within this context could be divided into three sections: (i) PB based photocatalytic water oxidation: In this work-package, an entirely precious metal-free chromophore-donor-water oxidation catalyst triad system is developed. The synthesis involves the coordination of a porphyrin derivative to a bridging Fe(CN)5 group, which is then reacted with cobalt ions to prepare a covalently linked chromophore-Prussian blue analogue (CoFe(CN)5–Ligand) assembly. Light-driven water oxidation studies in the presence of an electron scavenger indicate that the triad is active and maintains a steady activity for at least 3 hours. Transient absorption experiments and computational studies reveal that the Fe(CN)5 group is more than just a linker. It takes part in electron donation and co-operates with porphyrin in the charge separation process. (ii) PB based photoelectrochemical water oxidation: Here, we move one step forward and design a ruthenium-free water oxidation photoanode by the sensitization of titanium dioxide (TiO2) nanowires with a PB-organic chromophore ...