Degradation of Direct Black 38 dye under visible light and sunlight irradiation by N-doped anatase TIO2 as photocatalyst

The N-doped TiO2 photocatalyst was prepared by calcination of a hydrolysis product composed of titanium (IV) isopropoxide with ammonia as the precipitator. X-ray diffraction, surface area, XPS and UV–vis spectra analyses showed a nanosized anatase structure and the appearance of a new absorption band in the visible region caused by nitrogen doping. The degradation of Direct Black 38 dye on the nitrogen-doped TiO2 photocatalyst was investigated under visible light and sunlight irradiation. The N-doped anatase TiO2 demonstrated excellent photocatalytic activity under visible light. Under sunlight irradiation, the N-doped sample showed slightly higher activity than that of the non-doped sample. ► The degradation of Direct Black 38 dye on the N-doped TiO2 photocatalyst was investigated. ► The N-doped anatase TiO2 demonstrated excellent photocatalytic activity under visible light. ► The N-doped TiO2 showed slightly higher activity compared to non-doped TiO2.