Hydrothermal and Co-Precipitation Combined with Photo-Reduced Preparation of Ag/AgBr/MgBi₂O₆ Composites for Visible Light Degradation Toward Organics

This study developed a MgBi₂O₆-based photocatalyst via low-temperature hydrothermal synthesis. AgBr was co-precipitated onto MgBi₂O₆, and silver nanoparticles (AgNPs) were photo-reduced onto the surface. The photocatalytic performance, assessed by methylene blue (MB) degradation under white-light LED irradiation (2.5 W, power density = 0.38 W/cm²), showed that Ag/AgBr/MgBi₂O₆ achieved 98.6% degradation in 40 min, outperforming MgBi₂O₆ (37.5%) and AgBr/MgBi₂O₆ (85.5%). AgNPs boosted electron-hole separation via surface plasmon resonance, reducing recombination. A Z-scheme photocatalytic mechanism was suggested, where photogenerated carriers transferred across the p–n heterojunction between AgBr and MgBi₂O₆, producing reactive oxygen species like superoxide and hydroxyl radicals critical for dye degradation. Thus, the Ag/AgBr/MgBi₂O₆ composites possessed excellent photocatalytic performance regarding dyestuff degradation (85.8–99.9% degradation within 40 min) under white-light LED irradiation.