Fabrication of Z-scheme Bi5O7I/MIL-53(Fe) hybrid with improved photocatalytic performance under visible light irradiation

A series of Bi5O7I/MIL-53(Fe) (BOI/MIL-w) composites were successfully prepared by a facile in-situ solvothermal approach. The matched energy bands enabled Bi5O7I and MIL-53(Fe) to form a Z-scheme heterojunction which resulted in an efficient separation of the photo-induced electron-hole pairs. The photocatalytic activity of BOI/MIL-w was evaluated by the degradation of Rhodamine B (RhB) in water under the visible light irradiation. Compared with Bi5O7I, photocatalytic performances of BOI/MIL-w notably boosted. When the content of added MIL-53(Fe) was 3 wt%, BOI/MIL-3 presented the highest activity with a degradation efficiency of 99.7% only after 60 min of irradiation. The reaction rate constant k could reach 0.0992 min(-1) which was nearly 12.6 times as high as that of Bi5O7I. Moreover, BOI/MIL-w had a good stability and reusability, which could ensure its practical application. Trapping experiments confirmed that h(+) and center dot O-2(-) were the dominant active species during the photocatalytic process, and further demonstrated the formation of the Z-scheme heterojunction facilitated the photocatalytic performance of BOI/MIL-w.