Self-Assembly of Porous Hierarchical BiOBr Sub-Microspheres for Efficient Aerobic Photooxidation of Benzyl Alcohol under Simulated Sunlight Irradiation

Semiconductor photocatalytic performances can be modulated through morphology modification. Herein porous hierarchical BiOBr microspheres (BiOBr-MS) of ~3 μm was firstly self-assembled without the assistance a template via facile solvothermal synthesis in triethylene glycol (TEG) at 150 °C for 3 h. KBrO3 exploited as bromine source, which slowly provided bromide ions upon reduction TEG and controlled growth self-assembly primary nanoplates. The addition PVP during BiOBr-MS reduced particle size by about three-fold to generate sub-microspheres (BiOBr-sMS) <1 μm. BiOBr-sMS exhibited significantly higher activity than aerobic photooxidation benzyl alcohol (BzOH) benzaldehyde (BzH) under simulated sunlight irradiation (conversions BzOH (50 mM) over were, respectively, 51.3% 29.6% with 100% selectivity BzH after Xenon illumination 2 h 25 °C). photogenerated holes ·O2− were found main reactive species oxidation spheres scavenging tests spin-trapping EPR spectra. attributed its more open structure, efficient charge separation, negative conduction-band position generation larger amounts ·O2−.