Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Physical Chemistry

Different morphologies of nanostructured TiO₂ photoanodes were prepared for water splitting application. Highly crystalline, TiO₂ pristine sub-10 nm anatase nanocrystals were fabricated at low temperature by post hydrothermal treatment of the as-prepared TiO₂ nanoparticles. This treatment resulted in bandgap narrowing and increased photocurrent density value (3.8 mA/cm²) when this material was employed in water splitting systems. The achieved photocurrent values are among the highest reported ones so far for the fabricated nanoparticles at this low temperature. This might be explained by the increased surface defects of the prepared nanoparticles. It resulted in bandgap narrowing that was further investigated using positron annihilation experiments by measuring positron lifetime and doppler broadening. Also stable TiO₂ nanotubes (TNTs) with length ~2 æm have been fabricated using an ethylene glycol electrolyte with low water content by anodization technique. The TNTs were decorated by gold nanoparticles (NPs) using magnetron sputtering in argon atmosphere at different deposition currents for enhancing the visible light photoactivity of TNTs by the surface plasmonic effect of metal nanostructures which showed maximum PCE of 0.15% AM 1.5

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