WO₃ Nanorod-Doped Hexagonal ZIF-67@ZIF-8 Metal–Organic Frameworks: A Z-Scheme Heterostructure for Enhanced Photocatalytic Degradation of Tetracycline under Visible Light

As healthcare systems continue to grow, the overuse of antibiotics poses a rising threat of water contamination. Designing a suitable catalyst remains a bottleneck for their efficient photocatalytic degradation. Herein, we constructed a Z-scheme heterojunction for antibiotic degradation under visible light irradiation. A WO₃@ZIF-67@ZIF-8 nanocomposite was created by hydrothermally immobilizing WO₃ nanorods produced by a coprecipitation technique onto ZIF-67@ZIF-8 metal-organic frameworks. Uneven distribution of WO₃ across the hexagonal structure of ZIF-67@ZIF-8 was found by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The composites photocatalytic activity in degrading tetracycline was significantly higher than that of ZIF-67@ZIF-8 or WO₃ alone. A Z-scheme mechanism, confirmed via Mott-Schottky analysis, facilitated the degradation, and the catalyst showed strong stability, retaining performance after four reuse cycles. This study lays forth a feasible strategy for synthesizing a Z-scheme zeolite-based catalyst to effectively eradicate pollutants from water.