Facile construction of Fe3+/Fe2+ mediated charge transfer pathway in MIL-101 for effective tetracycline degradation

Abstract

Semiconductor-based photocatalyst, whose efficiency distinctly hinges on the separation of photoinduced charge transfer within the interface of bulk structure, has incurred some intractable issues due to the existing energy barrier. Regulating the structure of MOF reasonably would feature an accelerated charge separation, and an effective utilization of photogenerated charges. Herein, a new type of MOF with both interior linker and metal valence modulation (m-MIL-101–1.0) is reported to boost photocatalytic activity owing to the formed charge migration pathway. At first, we introduced defective sites via CTAB, which acted as exposed sites for further reduction reaction. Then, NaBH4 was used to achieve metal valence regulation. Benefiting from the unique structure, the Fe3+/Fe2+ redox center was considered as a driving force to facilitate the charge transfer. It is properly considered that the activity improvement is attributed to the synergistic effect of both internal and external charge transfer channels. As a result, such m-MIL-101–1.0 has a higher activity than that of MIL-101 for photocatalytic degradation of tetracycline in water. We envision this interior configuration would be an ideal paradigm for tuning the activity of MOFs and extending the boundaries of MOF-based photocatalysts.