Flower-like NiFe layered double hydroxide/Bi2WO6 S-scheme heterojunction for photodegradation of ciprofloxacin under visible light

Photocatalytic degradation stands as an effective remedy to solve the global environmental pollution caused by organic pollutants. In this study, we synthesized a NiFe layered double hydroxide/Bi₂WO₆ (NF-LDH/BWO) Step-scheme (S-scheme) heterojunction. The attachment of NF-LDH particles on flower-like BWO increased the active sites and the interface area between two pure materials. The construction of LDH/BWO heterojunction endowed with improved light absorption capacity and boosted separation efficiency of photo-generated carriers. Consequently, compared with BWO and NF-LDH, the NF-LDH/BWO composites showed enhanced photoactivities. At NF-LDH mass ratio of 10%, the optimal degradation rate of ciprofloxacin (75.9%) within 60 min under visible illumination was achieved, 1.43- and 9.37-fold those of BWO and NF-LDH, respectively. In addition, the NF-LDH/BWO composite also demonstrated excellent cyclic stability. The S-scheme mechanism was proposed based on both experimental and density functional calculation results.