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Future sustainable energy scenarios require an improved access to renewable energy sources and thuds help to reduce the carbon footprint of the energy sector. The dream concerning the implementation of a solar photocatalytic system combining the conversion of aqueous organic pollutants into value-added fuels, i.e., H2, is still far from being realized because of technical, materials and reaction-mechanistic related issues. Titanium dioxide is one of the most widely used semiconductor photocatalysts, however, modification of its properties is required to take place to overcome the limits of its efficient exploitation. In this thesis, TiO2 capable of noble-metal-free photocatalytic H2 evolution was successfully synthesized while optimizing the Evaporation-Induced Self-Assembly (EISA) method with the help of the Design of Experiment (DoE) statistical methodology. Applying the outputs of DoE, i.e., combining F-108 block copolymers with titanium(III) chloride as precursor, resulted in a TiO2 exhibiting photocatalytic H2 generation from aqueous ethanol solution. This unexpected photocatalytic performance is mainly attributed to the presence of new defects, i.e., Ti(II) species at the particle surface and most likely in interstitial positions. These defects resulting in a high density of charge carriers exhibiting longer lifetime, a high number of surface trapped states of holes, and a shift of the flat band potential to a more negative potential. The thus synthesized TiO2 was used to investigate the mechanistic aspects of H2 production via the photocatalytic reforming of oxalic acid. The photocatalytic oxidation of aqueous oxalic acid was studied employing different photocatalytic systems under constant pH conditions. The fast photo-oxidation of oxalic acid on bare TiO2 in O2-reach conditions was achieved without the detection of by-products, however, the reaction rates were about 60-fold and 7-fold lower on bare TiO2 and Pt/TiO2, respectively, in O2-free photocatalytic systems. In such a system exhibiting lower ...