One-pot synthesis of BiOCl microflowers co-modified with Mn and oxygen vacancies for enhanced photocatalytic degradation of tetracycline under visible light

Visible light photocatalysis is one of the promising green strategies to settle the global energy and environmental crisis. Herein, BiOCl microflowers co-modified with oxygen vacancies (OVs) and Mn2+ were synthesized via a simple one-pot solvothermal method. The phase structures, morphologies, chemical states, light absorption properties and photoelectrochemical behaviors of the prepared materials were systematically characterized. The photocatalytic activity was evaluated by degrading tetracycline under visible light irradiation. It was revealed that the BiOCl samples fabricated by the solvothermal method showed the morphology of 3D microflowers. Compared with the BiOCl prepared via the hydrothermal route, these microflowers had lower crystallinity and higher visible light absorption capacity. Additionally, both the degradation of tetracycline and the photocurrent response were significantly improved in the case of co-modified BiOCl. This was because the shift of absorption edge towards longer wavelength could promote to generate more charge carriers. Another reason might be that the defect/impurity energy levels introduced by forming OVs/doping Mn2+ could capture the photoexcited electrons and holes to retard their recombination. Furthermore, the conduction band and valence band of BiOCl could be concurrently adjusted to narrow its band gap. Therefore, the improved photocatalytic performance might derive from the enhancement of visible light absorption and the effective separation of photo-generated charge carriers.