Synthesis and Photocatalytic Properties of BiOX0.5Y0.5 (X, Y = Cl, Br and I) for Congo‐Red Degradation

Bismuth halide oxides BiOX (X = Cl, Br, I) have attracted the greater interest from the field of photocatalysis, but there are few reports about Bi di‐halogenated oxides. In this study, a series of Bi di‐halogenated oxides (BiOX x Y 1‐x ) photocatalysts was synthesized, the synthesis parameters were optimized, and the optimum proportion of halide elements was determined to be 0.5:0.5. The bandgap and light absorption wavelength range of Bi di‐halogenated oxides could be regulated, and the prepared materials showed much better photocatalytic performance for photodegradation of Congo‐red (CR). The degradation rate of CR reached to 97.9% in 30 min by the best sample (BiOBr 0.5 I 0.5 ) under simulated sunlight. The main reason for the high photocatalytic activity was that the bandgap of the BiOBr 0.5 I 0.5 was obviously narrowed, the absorption range of visible light was widened, and the specific surface area was increased by lamellar structure. The I and Br elements were inserted into the intermediate layer of [Bi 2 O 2 ] 2+ in BiOBr 0.5 I 0.5 rather than being a simple composite of BiOBr and BiOI, and this precisely represented the innovation of this research.