Cr/S/TiO₂-LOADED HOLLOW GLASS MICROSPHERES AS AN EFFICIENT AND RECYCLABLE CATALYST FOR THE PHOTOCATALYTIC DEGRADATION OF INDIGO CARMINE UNDER VISIBLE LIGHT

Chromium and sulfur co-doped nanometer TiO₂ hollow glass microspheres (Cr/S/TiO₂-HGM) were synthesized by a sol-gel method. Characterization used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N₂ adsorption-desorption (Brunauer-Emmett-Teller (BET) measurements) and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity was evaluated by photodegradation of indigo carmine in an aqueous solution under visible light irradiation. The results indicated that the Cr/S/TiO₂ containing 0.60% (atomic ratio) chromium and 1.2% (atomic ratio) sulfur calcined at 500 ºC for 2 h had high catalytic efficiency under visible light irradiation. The floating Cr/S/TiO₂-HGM catalyst had greater photocatalytic activity than Cr/S/TiO₂ powder. Therefore, Cr/S/TiO₂-HGM is a promising, high-performing, visible-light-driven, and more reusable photocatalyst.

Keywords:
hollow glass microspheres; visible light; indigo carmine; TiO₂; photocatalytic degradation