Eu/Fe Co-doped Bi2WO6 nanocatalyst: Synergistic photo-Fenton catalysis for rapid dye degradation with robust pH tolerance and ecological safety

This study reports an innovative europium-iron co-doped bismuth tungstate catalyst (EF-Bi 2 WO 6 ) for rapid organic pollutant degradation through a visible light-driven photo-Fenton process. The results of degradation experiment verified that the 1-EF-BWO catalyst exhibited superior photo-Fenton catalytic activity relative to single-doped and undoped Bi 2 WO 6 , achieving over 99 % degradation of Rhodamine B (RhB) within 6 min, with a kinetic rate constant of 0.9745 min −1 , which was 4.81 times higher than pure Bi 2 WO 6 (0.1678 min −1 ) and 2.42–2.92 times superior to Eu- or Fe-doped Bi 2 WO 6 . Remarkably, 1-EF-BWO maintained consistent degradation efficiency across a broad pH value and diverse ionic environments, showcasing robust operational adaptability. The enhanced catalytic activity is attributed to synergistic electron transfer mechanisms between Eu 3+ , Fe 3+ , and the Bi 2 WO 6 matrix, which optimized band gap structure to facilitate charge carrier separation. EPR spectroscopy revealed that singlet oxygen ( 1 O 2 ), photogenerated holes (h + ), and superoxide radicals (·O 2 − ) served as the primary reactive species driving pollutant mineralization. Reusability tests demonstrated remarkable catalytic stability over multiple cycles. Phytotoxicity assessments revealed that EF-Bi 2 WO 6 -treated wastewater significantly enhanced mung bean germination rates, underscoring its ecological compatibility for sustainable wastewater remediation. These results establish EF-Bi 2 WO 6 as a sustainable, pH-tolerant nanocatalyst with dual advantages of ultrafast degradation kinetics and environmental safety.