Z-scheme Bi₄O₅Br₂/NH₂-MIL-125(Ti) heterojunctions enable exceptional visible photocatalytic degradation of organic pollutant

One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions. Herein, novel Bi₄O₅Br₂/NH₂-MIL-125(Ti) Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant photodegradation. The NH₂-MIL-125(Ti) nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi₄O₅Br₂. The as-prepared Bi₄O₅Br₂/NH₂-MIL-125(Ti) presents more than 90% degradation of various pollutants, outperforming the counterpart individual ones. The various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials, in which the migration path of carriers from the material's interior to the surface can be reduced, in turn enhancing migration efficiency and separation capability significantly. A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors, radical trapping experiments and liquid chromatography mass spectrometry analysis. This work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts, as well as the effective purification of wastewater in environmental remediation.