Synthesis of Ta2O5/TiO2 Coupled Semiconductor Oxide Nanocomposites with High Photocatalytic Activity

Ta2O5/TiO2 coupled semiconductor photocatalysts, with different Ta:Ti ratios were prepared by simple solid-solid reaction technique. These as prepared catalysts were characterized by diffuse reflectance UV-Visible spectroscopy, X-ray diffraction, FTIR and FE-SEM techniques. The effect of Ta:Ti mole ratios on the photocatalytic activity of Ta2O5/TiO2 coupled composites was studied by following the degradation of aqueous methylene blue dye. The optical properties of these as prepared coupled photocatalysts were found to have close similarity with TiO2 and the corresponding bandgap value observed for coupled semiconductors was 3.15 eV. FESEM image showed uniform distribution of Ta2O5 in TiO2 matrix with spherical morphology having 50-140 nm particle size. Higher photocatalytic activity was observed for Ta2O5/TiO2-coupled composites towards methylene blue (MB) degradation as compared to that of individual Ta2O5 and TiO2. Among the prepared compositions of Ta2O5/TiO2, the composite having Ta:Ti ratio 1:99 showed highest rate of reaction for photocatalytic MB degradation (5.74 x 10(-2) min(-1)).