To improve the catalytic activity and recovery efficiency of photocatalysts, the Bi₄O₅Br₂ was decorated on SrFe₁₂O₁₉ via a microemulsion method to synthesize a novel magnetic Bi₄O₅Br₂/SrFe₁₂O₁₉ nanocomposite. The microstructures, morphological characteristics, photoelectrochemical properties, magnetic performance and photocatalytic mechanism of catalysts were investigated by various techniques. The photocatalytic experiments presented that the Bi₄O₅Br₂/SrFe₁₂O₁₉ photocatalyst with 5 wt.% of SrFe₁₂O₁₉ has the best capacity for degrading Rhodamine B (RhB). The activity of the photocatalyst was increased by the optimization of energy band structure and the formation of an internal electric field in the type-II heterojunction. Moreover, the h⁺ and ·O₂^- were demonstrated to be the primary active constituents in the photocatalytic reaction by the energy-band structure analysis and radical scavenging experiments. The saturated magnetizing strength (Ms) and the recovery rate of composite photocatalyst were 2.76 emu·g^-1 and 88.2% respectively, which confirmed that the nanocomposite has excellent magnetic property. Meanwhile, the photodegradation rate was still 84.6% after five circulating tests, which demonstrated that the sample has the superior photo-stability performance. This paper offers a new approach to the synthesis of the composite magnetic photocatalyst based on Bi₄O₅Br₂, and some guidance for the photocatalytic degradation mechanism.

为了提高光催化剂的催化活性和回收效率，通过微乳化法将Bi ₄ O ₅ Br ₂装饰在SrFe ₁₂ O ₁₉上，合成了新型的磁性Bi ₄ O ₅ Br ₂ / SrFe ₁₂ O ₁₉纳米复合材料。通过各种技术研究了催化剂的微观结构，形态特征，光电化学性能，磁性能和光催化机理。光催化实验表明Bi ₄ O ₅ Br ₂ / SrFe ₁₂ O ₁₉具有5 wt。％SrFe ₁₂ O _19的光催化剂具有最佳的罗丹明B（RhB）降解能力。通过优化能带结构和在II型异质结中形成内部电场，提高了光催化剂的活性。此外，将H ⁺和·O2 ₂ ^-被证明是由能带结构分析和自由基清除实验的光催化反应的主要活性成分。复合光催化剂的饱和磁化强度（Ms）和回收率为2.76 emu·g ^-1分别为88.2％和88.2％，这证实了纳米复合材料具有优异的磁性。同时，经过五次循环测试，光降解率仍为84.6％，表明该样品具有优异的光稳定性能。本文为基于Bi ₄ O ₅ Br ₂的复合磁性光催化剂的合成提供了一种新方法，并为光催化降解机理提供了一些指导。