MOF-derived Co₃O₄@P-doped carbon nitride/ α-Fe₂O₃ nanocomposite as a dual Z-scheme photocatalyst for persulfate mediated Bisphenol-A degradation

In this study, a Co₃O₄/phosphorus-doped g-C₃N₄/α-Fe₂O₃ (Co₃O₄@P-CN/α-Fe₂O₃) composite was synthesized by a two-step method using respective MOF precursors. Initially, amine-functionalized Fe-MOF (Fe-MIL-88b) was co-condensed with phosphonitrilic trimer and melamine in the presence of triethylamine, resulting in a crosslinked polymer of phosphazene-coated Fe-MIL88b (Pz/Fe-MIL-88b). Subsequent Pz/Fe-MIL-88b calcination at 550 °C yielded a P-doped g-carbon nitride (P-CN)/α-Fe₂O₃ composite. Furthermore, ZIF-67 was co-doped with the P-CN/α-Fe₂O₃ composite through ultrasonic dispersion, followed by thermal calcination at 350 °C, yielding Co₃O₄@P-CN/α-Fe₂O₃. However, the hybrid ternary composite exhibited a dual Z-scheme heterojunction in persulfate (PS)-mediated bisphenol-A (BPA) degradation under visible light. Co₃O₄@P-CN/α-Fe₂O₃ demonstrated superior degradation efficiency (99.3 % ) with rapid photocatalytic kinetics (0.0663 min⁻¹) for BPA degradation compared to the binary composite and P-CN. The magnetic Co₃O₄@P-CN/α-Fe₂O₃ composite exhibited high structural stability and reusability, achieving over 95 % BPA degradation after five cycles under visible light.