A microwave-assisted solvothermal method to synthesize BiOCl microflowers with oxygen vacancies and their enhanced photocatalytic performance

The photocatalytic performance of the catalysts are highly dependent on their morphology and the separation efficiency of photo-generated carriers. In this work, the self-assembled BiOCl microflowers with oxygen vacancies (OVs) were synthesized by facile microwave-assisted solvothermal method. The ethylene glycol was applied as solvent, reductant and soft templates of microflowers. As the preparation temperature increased from 100 ℃ to 160 ℃, the morphology of BiOCl was transformed from microflowers to nanosheets, and the concentration of OVs increased gradually. The photocatalytic performance of BiOCl was evaluated by photocatalytic degradation of Rhodamine B (RhB), Methylene blue (MB) and Ciprofloxacin (CIP) under visible light irradiation. It is indicated that the excessive OVs would inhibit the separation and migration of photo-generated carriers. Benefiting from the optimum OVs concentration and enhanced specific surface area, the BiOCl-100 microflowers exhibited a superior photocatalytic performance. The degradation constants for RhB, MB and CIP by BiOCl-100 were estimated to be 0.512, 0.022 and 0.022 min−1, which were 4.3, 1.7 and 5.5 folds higher than BiOCl-100-w nanosheets (with no OVs), respectively. This work demonstrated the superior photocatalytic performance of BiOCl microflowers with optimum OVs, which could be also applied to design of other highly efficient photocatalysts.