Transformation of Commercial TiO₂ into Anatase with Improved Activity of Fe, Cu and Cu-Fe Oxides Loaded TiO₂.

In the present study copper and iron oxides loaded TiO₂ catalysts are prepared by the deposition-precipitation method (DP) and the photocatalytic efficiency of these catalysts are tested for the degradation of Rose Bengal dye (Acid Red 94) under sunlight. The catalysts are characterized by XRD, TEM and UV-vis diffuse reflectance spectral analysis. It is interesting to note that the rutile form of commercial TiO₂ is competently converted into anatase after loading oxides of Cu, Fe and Cu-Fe on TiO₂ as evident from XRD analysis. This result is consistence with the result obtained in UV-vis diffuse reflectance spectra. TEM analysis confirms the nano particles of Cu and Fe deposited on TiO₂. Photocatalytic studies were performed in a batch reactor under solar radiation. Preliminary studies are performed to understand the photocatalytic degradability of the dye and optimization of catalyst weight and dye concentration. Kinetic studies were done at different dye concentrations and it was found that the rate equation followed first order kinetics and obeyed Langmuir-Hinshelwood model. The comparison of the activity of blank TiO₂, copper or/and iron oxides loaded TiO₂ catalysts showed that the Cu and Fe oxide loaded catalysts are more active than pure TiO₂ and also the Cu-Fe oxides co-loaded TiO₂ catalysts showed much best activity. The order of activity of the catalysts is in the following order: Cu-Fe/TiO₂ > Fe/TiO₂ > Cu/TiO₂ > TiO₂. The enhanced activity of metal oxide loaded TiO₂ is attributed to the presence of TiO₂ in anatase form after loading, which enhanced the charge transfer from the TiO₂ to adsorbed molecules for reaction.