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 TiO₂and the corresponding bandgap value observed for coupled semiconductors was 3.15 eV. FESEM image showed uniform distribution of Ta₂O₅in 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 × 10^–2 min^–1).