Facile NaBH4-cu dual modification of CoFe Prussian blue analogues for enhanced peroxymonosulfate activation toward tetracycline degradation

Tetracycline hydrochloride (TCH), as a representative antibiotic pollutant, poses significant environmental risks due to its persistence and ecotoxicity. Conventional degradation technologies are often hampered by inefficiency and high operational costs. To overcome these limitations, a simple sodium borohydride (NaBH 4 ) reduction method was employed to modify CoFe Prussian blue analogue (CoFe-PBA), significantly its intrinsic activity. Subsequently, low-level Cu loading (2 wt%) was introduced, further substantially boosting the degradation efficiency. Comprehensive characterization confirmed that this sequential modification optimizes the material structure and enhances the density of active sites. The optimized 2 %Cu/CoFe PBA catalyst efficiently activated peroxymonosulfate (PMS), achieving >96 % TCH removal within 30 min under optimal conditions. In addition, the 2 %Cu/CoFe PBA exhibited excellent stability across a broad pH range (5–11) and in complex anionic environments. Radical quenching experiments and mechanism analysis revealed that non-radical singlet oxygen ( 1 O 2 ) and sulfate radical (SO 4 · − ) pathways were the dominant contributors to TCH degradation, with superoxide radical (O 2 · − ) and hydroxyl radical (∙OH) playing comparatively minor roles. This high performance stems from synergistic Fe/Co/Cu interactions promoting efficient PMS activation. This work provides a facile, efficient modification strategy (NaBH 4 reduction and minimal Cu loading) for PBAs and clarifies the predominant reactive species responsible for high-performance antibiotic degradation.