Enhanced photocatalytic activities of TiO2 nanocomposites doped with water-soluble mercapto-capped CdTe quantum dots

CdTe quantum dots (QDs)-doped TiO2 photocatalysts were synthesized by a facile sol–gel method at room temperature and characterized by fluorescence spectroscopy, UV–vis diffuse reflectance spectroscopy, Hadamard transform imaging microscopy, FT-IR, XRD, FE-SEM, HRTEM, XPS and nitrogen sorption spectroscopy. The photocatalytic activities were investigated by degrading malachite green (MG) in aqueous solution under halogen–tungsten lamp irradiation. The results revealed that the catalysts exhibited much higher photocatalytic activities than both controlled TiO2 (without doped QDs) and P25 (TiO2, Degussa). It was found that the catalyst doped with 0.06 wt% CdTe QDs had the highest photocatalytic activity. According to the structural and surface analyses, the enhanced photocatalytic activities could be attributed to its strong absorption and low recombination rate of the electron–hole pairs because of the heterojunction formed by CdTe QDs and TiO2. All the adsorption isotherms demonstrated the Langmuir type behavior. The study presented new types of photocatalysts for environmental applications.

Figure optionsDownload as PowerPoint slideResearch highlights▶ Adsorption ability are in the order CdTe-0.06-TiO2 > controlled TiO2. ▶ CdTe-0.06-TiO2 is red-shifted to the visible region. ▶ CdTe-0.06-TiO2 gives good crystalline structures and surface. ▶ CdTe-0.06-TiO2 has more absorption of light.