Novel 2D/2D BiOBr/UMOFNs direct Z-scheme photocatalyst for efficient phenol degradation.

A novel 2D/2D BiOBr/ultrathin metal-organic framework nanosheets (UMOFNs) direct Z-scheme photocatalyst was successfully synthesized by using a simple deposition-precipitation method. The photocatalytic performance was evaluated under light irradiation, which revealed that the 2D/2D BiOBr/UMOFNs Z-scheme photocatalyst exhibits higher photocatalytic degradation of phenol compared to pristine BiOBr and UMOFNs. A BiOBr/UMOFNs-40% (mass ratio for BiOBr and UMOFNs of 1:0.4) photocatalyst was found to show the best photocatalytic degradation efficiency and stability, reaching 99% phenol degradation under light irradiation of 270 min and maintaining 97% degradation after 5 recycling runs. Results obtained from a trapping experiment and electron paramagnetic resonance suggest that reactive OH and O-2(-) play a major role in phenol degradation. Photoluminescence and photocurrent results reveal that the excellent photocatalytic activity of the 2D/2D BiOBr/UMOFNs photocatalyst can be ascribed to the efficient separation of photogenerated electron-hole pairs through a direct Z-scheme system. This article provides a possible reference for designing Z-scheme photocatalysts by using MOFs and semiconductors for practical organic pollutant treatment.