Synthesis of magnetically recyclable g-C3N4/NiFe2O4 S-scheme heterojunction photocatalyst with promoted visible-light-response photo-Fenton degradation of tetracycline

• NFO nanoparticles with the narrow band gap could effectively enhance the visible light absorption of CN nanosheets; • S-scheme interfacial charge transfer mechanism achieves spatial separation of carriers retaining strong redox capacity over g-C 3 N 4 /NiFe 2 O 4 heterojunction; • The photo-Fenton synergistic effect promotes the conversion of Fe 3+ and Fe 2+ in the CB of NFO to generate more ·OH. The synergy of photocatalysis and Fenton reaction is an effective strategy for the degradation of harmful antibiotic wastewater. In this study, the magnetically recyclable g‐C 3 N 4 /NiFe 2 O 4 S-scheme heterojunction photocatalyst was successfully prepared by the hydrothermal method. The photo-Fenton degradation experiments show that the synthesized g‐C 3 N 4 /NiFe 2 O 4 photocatalyst can significantly improve the degradation effect of tetracycline (TC) under visible light. The high catalytic activity of g‐C 3 N 4 /NiFe 2 O 4 photocatalyst is not only due to the photo-Fenton synergistic effect, but also result from the establishment of S scheme heterojunction between g‐C 3 N 4 and NiFe 2 O 4 , which can directly accelerate the transfer of photogenerated electrons from NiFe 2 O 4 to g‐C 3 N 4 , and further increases the photocatalytic reaction rate. This photo-Fenton degradation system of magnetic recyclable g‐C 3 N 4 /NiFe 2 O 4 heterojunctions constructed in this study will provide a new design idea for environmental protection and efficient treatment of antibiotic wastewater.