Synthesis of Anatase/Brookite Mixed Phase TiO2 Nanostructures and its Photocatalytic Performance Study

The TiO2 nanostructures were prepared using hydrothermal reaction technique at different reaction temperatures viz., 120 degrees C, 160 degrees C, and 200 degrees C for 24 h. The synthesized TiO2 nanostructures was characterised by various spectroscopic techniques. XRD indicate the formation of highly crystalline nano size particles of anatase phase of TiO2 along with minor percentage of brookite phase. Diffuse reflectance UV-Visible spectroscopy depicts the band gap around 3.2 eV. The FE-SEM shows formation of spherical particles having size in the range of 5 to 10 nm, however the small particles tend to agglomerate leading to the formation of submicron size clusters. TEM analysis confirms the formation of nanostructured TiO2 having size in the range of 5 to 10 nm with distorted spherical shaped morphology. The photocatalytic performance of the synthesized TiO2 was investigated by observing the degradation of aqueous methylene blue (MB) dye and H-2 generation via water splitting under 400 W mercury vapour lamp respectively. Among the prepared samples, the TiO2 prepared at 160 degrees C, showed highest MB degradation (97 %) within 1 h of irradiation time. The photocatalytic H-2 generation via water splitting was also investigated and found to be highest for TiO2 prepared at 160 degrees C, the observed rate of H-2 generation was 3848 mu mol/0.1 g in 4 h is almost twelve fold higher than the pure anatase phase.