Improved photocatalytic activity of Bi2O3 composites derived from a layered precursor

ZnO/Al2O3/Bi2O3 mixed-metal oxide (ZnAlBi-MMO) has been successfully prepared by the coprecipitation method and controllable calcination. Powder X-ray diffraction, high-resolution transmission electron microscopy and UV–Vis diffuse reflectance spectra confirmed the structure of as-synthesized solids. The results reveal that the synthetic methods can provide the heterostructure of MMO. The photocatalytic activity of ZnAlBi-MMO was evaluated by the photodegradation of methylene blue (MB) under visible light irradiation. Factors that may affect the photodegradation behavior were studied such as calcination temperature, catalyst dose and pH. Furthermore, the stability of synthesized photocatalysts was investigated by studying the photocatalytic ability of reclaimed ZnAlBi-MMO. The results showed the removal efficiency of MB was higher than 83 % even after four successive photoreactions, demonstrating the great potential of layered double hydroxides as catalyst supports. The possible mechanism underlying the enhanced photocatalytic activity of Bi2O3 was also discussed.