Fabrication of novel AgBr/Bi₂₄O₃₁Br₁₀ composites with excellent photocatalytic performance

Novel porous AgBr/Bi₂₄O₃₁Br₁₀ (AB/BOB) heterojunction composites were prepared by a hydrothermal calcination-ion exchange route and their physico-chemical properties were characterized by XRD, XPS, SEM, EDX, UV-vis DRS, BET and electrochemical measurements. The photocatalytic activity of the composites consisting of different AB/BOB mass ratios was evaluated by degradation of methylene blue (MB) under visible light irradiation. Compared with pure AB and BOB, the porous 20% AB/BOB composite exhibits much enhanced photocatalytic activity with good cycling stability. The significant enhancement in photoactivity is contributed to by both a high adsorption capacity and the separation efficiency of photo-generated electron-hole (e^--h⁺) pairs via a Z-scheme mechanism. In addition, radical scavenging experiments confirm that the reactive ·OH radicals play an important role in the photocatalytic reaction. The novel (AB/BOB) heterojunction composites could have a promising application in treatment of various dyestuff wastewaters on a large scale.