Significance of the surface and bulk features of hierarchical TiO2 in their photocatalytic properties

Abstract Solvothermal crystallization is an adequate approach for preparing differently shaped TiO2 crystalline materials because it is highly sensitive to the synthesis parameters change. This study presents two sample series, one prepared from tetraisopropyl orthotitanate TTIP and one from tetrabutyl orthotitanate TBU. The influence of the applied temperature, different capping agents' amount, and the precursor volume ratio affected the measured characteristics (crystal phase composition, primary crystallity size, morphology, surface chemistry and optical properties). Although the samples revealed strong differences in crystal phase and size distribution, mostly spherical hierarchical morphology was achieved. The as-prepared samples were applied in photocatalytic processes to assess their efficiency under UV light and examine the influence of the structural features on the photocatalytic process. Not only the chosen precursor but the subtle changes in the listed parameters resulted in catalytical performance differences. Besides the crystal phase composition and the Ti3+ and Ti4+ species, it was found that organic surface particularities influenced the semiconductors’ photocatalytic performance.