Study of the preparation of TiO2 powder by different synthesis methods

In this work, we present a study on the preparation of TiO2 powder employing different synthesis methods as molten salt, sol-gel, combustion and hydrothermal. The structural, morphological, optical and surface properties were studied in order to evidence the characteristic of the TiO2 powder. By the molten salt method, the TiO2 powder presented a rutile-phase crystal structure with particles of micrometric size and low superficial area. When the combustion and sol gel methods were employed, the TiO2 powder had an anatase phase with a crystallite size of similar to 14 nm. Different morphologies such as nanocuboids, nanobelts, nanoparticles and interconnected nanobubbles were observed. The photocatalytic activity of TiO2 powder was assessed by the rhodamine B degradation. SG-TiO2 powder showed the highest photocatalytic efficiency in comparison with the rest of the samples. The presence of intrinsic defects and hydroxyl groups plays a fundamental role in the photocatalytic activity of the TiO2 powder.