indium doped and carbon modified p25 nanocomposites with high visible-light sensitivity for the photocatalytic degradation of organic dyes

The commercially available TiO 2 Degussa P25 was modified using a simple technique to produce a visible-light-actived indium and carbon doped P25 catalyst. The modified photocatalysts have been successfully obtained by thermal heating method. These as-obtained products were successfully characterized by X-ray diffraction (XRD), X-ray photoelectrion spectroscopy (XPS), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy respectively. The photocatalytic activities of all prepared catalysts were evaluated b y the degradation of organic dyes including methylene blue (MB) and Reactive Red 4 (RR4) under visible light irradiation. As the result shown, the indium and carbon co-doped on P25 nanocomposites possessed the extended light absorption in visible light and better charge separation capability as compared to the pristine P25. The optimum loading of In 3+ ions on P25 was 15%. Moreover, 15% In 2 O 3 /C-P25 showed the highest degradation rate of organic dye, which the removal efficiency can reach over 90% after 90 min and the corresponding hydrogen evolution rate of 15% In 2 O 3 /C-P25 was 9 times than P25. It was concluded that the synergistic effects of In 3+ ions and carbon narrowed the band gap of TiO 2 and promoted charge separation, which played a significant role for the enhancement of photoactivity. In addition, it was observed that the photo-degradation for all catalysts followed the first order reaction kinetics. Furthermore, the influence of initial pH values on the photocatalytic degradation of MB and RR4 using 15% In 2 O 3 /C-P25 catalyst was also investigated. Finally, the stability test of photocatalysts was carried out and the photocatalytic mechanism was explained concretely.