Two-dimensional polymerized carbon nitride coupled with (0 0 1)-facets-exposed titanium dioxide S-scheme heterojunction for photocatalytic degradation of norfloxacin

Poor visible light response and low separation efficiency of photogenerated carriers restricted the availability of titanium dioxide for antibiotic photodegradation, and the fabrication of two-dimensional/two-dimensional (2D/2D) heterojunction by coupling to a narrower bandgap semiconductor was an effective approach. Herein, a simple solvothermal method was used to grow 2D (0 0 1)-facets-exposed titanium dioxide ((0 0 1)-TiO2) nanosheets in situ on the surface of 2D polymeric carbon nitride (PCN) nanosheets to obtain PCN/(0 0 1)-TiO2 heterojunction for the photodegradation of norfloxacin. The synthesized heterojunction composites exhibited superior photodegradation performance, and the norfloxacin degradation rate reached up to 99% under simulated solar for 90 min. The efficient photocatalytic performance was attributed to the reduction of the bandgap and the formation of S-scheme heterojunctions, which enhanced the absorption of visible light and the carrier migration separation efficiency. Futhermore, the hierarchical 2D/2D nanosheet structure and the built-in electric field formed also sped up the charge transfer at the interface. This work presented a new viable solution to the problem of antibiotic contamination.