Lactic Acid Assisted Solvothermal Synthesis of BiOClxI1–x Solid Solutions as Excellent Visible Light Photocatalysts

A series of BiOCl x I 1– x ( x =0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) photocatalysts was firstly prepared by means of a facile solvothermal route with the help of lactic acid. The measured results show that the morphologies of the as-prepared samples are similar sheets with different thickness and diameters. Thinner nanosheets assembled flower-like BiOCl 0.5 I 0.5 solid solution exhibited the highest photocatalytic activity and stability among the prepared samples for the degradation of methylene blue(MB) and methyl orange(MO) under the illumination of visible light. The excellent photocatalytic properties of BiOCl 0.5 I 0.5 could be attributed to the high specific surface area, the suitable band gap energy and the lower recombination rate of the electrons and holes. In addition, catalyst BiOCl 0.5 I 0.5 was further used to degradate a more complicated mixed dye (MO+RhB+MB) system under visible light, displaying an excellent photocatalytic activity. Finally, the photocatalytic mechanism of catalyst BiOCl 0.5 I 0.5 to degradate colorful dyes was proposed. The trapping experiments of active species indicated that the holes are the main active species for the degradation of the mixed dyes.