Microwave-Assisted Hydrothermal Synthesis of Nanosheet-Assembled BiOBr and an Investigation of Photocatalytic Activity

Bismuth oxybromide (BiOBr), a layered semiconductor with good photogenerated carrier separation, is valuable for visible-light organic pollutant degradation. However, traditional hydrolysis-synthesized BiOBr has uneven particles, agglomeration, and insufficient active sites, limiting performance. This study used a microwave–hydrothermal method (adjusting time, temperature, power, pH) to prepare nanosheet-assembled BiOBr, characterized via XRD, SEM, Raman, and XPS. Under light irradiation, BiOBr primarily degrades Rhodamine B through direct oxidation by highly oxidative photogenerated holes, supplemented by the auxiliary oxidation of superoxide radicals. While maintaining a consistent catalyst loading, the optimal experimental conditions were applied (140 °C, 400 W, 10 min); 50–60 nm thick BiOBr achieved 95.4% RhB degradation (k = 0.03174 min−1) in 100 min, far better than traditional BiOBr (61.16%, k = 0.00917 min−1). This proves the method optimizes BiOBr performance.