Novel dual-effective Z-scheme heterojunction with g-C3N4, Ti3C2 MXene and black phosphorus for improving visible light-induced degradation of ciprofloxacin

Novel dual-effective Z-scheme heterojunction of graphitic carbon nitride/Ti3C2 MXene/black phosphorus (CN/MX/BP, CXB) was synthesized via a calcination process that achieved high photodegradation efficiency (> 99 %) of ciprofloxacin (CIP) under visible light irradiation (λ > 420 nm) within 60 min. The dual-effective CXB was reflected in the design of Z-scheme heterojunction and P-bridging effect, which were beneficial to form stable heterojunction and improve visible light-irradiated photocatalytic activity, including wider visible absorption range, faster carrier transfer and stronger redox ability. The P-bridging effect was designed from the reactions between the active P atom in the BP nanosheet and as-prepared CN (nitrogen deficiency). We rationally employed the binding energy shifts in X-ray photoelectron spectroscopy (XPS) and the redox ability of the photogenerated charges to prove the CXB was a Z-scheme heterojunction and the existence of P–N/P=N bonds. Moreover, the mechanisms of CIP degradation over the dual-effective Z-scheme heterojunction CXB were elucidated.