Solar photocatalytic degradation of dye wastewater in the presence of heat‐treated anatase TiO₂ powder

The phase transformation from anatase to rutile of titanium dioxide (TiO 2 ) was attempted by heat‐treatment and a novel TiO 2 catalyst with high photocatalytic activity under sunlight irradiation was obtained. The heat‐treated anatase TiO 2 powders at various transition stages were characterized by X‐ray diffraction (XRD), fourier transform infrared (FTIR), and transmission electron microscopy (TEM). The tests of photocatalytic activities of the heat‐treated anatase TiO 2 powders were conducted by the photocatalytic degradation of rhodamine B in aqueous solution under sunlight irradiation. The results reveal that the anatase TiO 2 powder heat‐treated at 700°C for 60 min shows the highest photocatalytic activity, which can effectively degrade rhodamine B in aqueous solution under sunlight irradiation. The remarkable improvement of photocatalytic activity of the anatase TiO 2 powders was mainly elucidated by the formation of special interphase between rutile and anatase phases, which can limit the recombination of photogenerated electrons and holes efficiently. Therefore, this method may be envisaged as a technology for treating dye wastewaters using solar energy.