Co₃O₄@CuO double core-shell hollow nanocages efficiently remove metronidazole by activating peroxymonosulfate under visible light

In this work, ZIF-67@Cu₂O was utilized as precursors to prepare the Z-scheme heterojunction of Co₃O₄@CuO double core-shell hollow nanocages. Co₃O₄@CuO catalysts can remove 50 mg/L of metronidazole (MNZ) by activating peroxymonosulfate (PMS) under visible light (Vis) in 25 min (99.9 %). The degradation kinetic constants of Co₃O₄@CuO were 39.86 and 4.69 times higher than those of Co₃O₄ and CuO, respectively, indicating that Co₃O₄@CuO showed excellent catalytic performance. Furthermore, Co₃O₄@CuO catalysts demonstrate enhanced light absorption capacity, facilitating increased excitation of ground-state electrons to improve catalytic efficiency. In Co₃O₄@CuO/PMS/Vis system, the Z-scheme charge transfer pathway accelerates charge transport and spatially separates electrons and holes, enhancing the photocatalytic performance of Co₃O₄@CuO. Additionally, Co₃O₄@CuO activated PMS to effectively degrade MNZ across a wide pH range (3−11) under visible light. Co₃O₄@CuO photocatalysts were adapted to complex water environments and demonstrated excellent stability through five successive degradation cycle experiments. Based on these results, the Co₃O₄@CuO photocatalysts provide valuable insights into antibiotic wastewater pollution treatment by activating PMS under visible light.