Lead (Pb2+) contamination in water severely endangers human health, thus demanding rapid and ultrasensitive detection methods. Herein, a magnetic CoFe2O4/Zn/Co@C composite was prepared via solvothermal synthesis of CoFe2O4, assembly with Zn/Co bimetallic MOFs (ZIF-67/ZIF8) and subsequent pyrolysis at 95℃ under N2 atmosphere. Comprehensive characterizations (XRD, SEM, TEM, VSM, BET) verified the composite featured uniform metal dispersion, a high specific surface area of 475.46 m2 \(\:\bullet\:\) g− 1, a saturation magnetization of 18.98 emu \(\:\bullet\:\) g−1 and a hierarchical bimodal porous structure (1.4 nm and 25 nm). Modified on a glassy carbon electrode (GCE), the resultant sensor exhibited excellent analytical performance for Pb2+ detection via differential pulse voltammetry (DPV): a wide linear range of 0.001–90 µM, an ultralow detection limit of 1.3 nM (8 times lower than the WHO drinking water standard) and a high sensitivity of 36.44 µA·µM−1cm− 2 (R2 = 0.99947). Moreover, the sensor showed superior practical performance with < 5% signal interference by 50-fold competing ions, 98.3% response retention after 7 days of room temperature storage, 2.13% relative standard deviation (RSD) for 6 independent electrodes, and 99.5–103.4% recovery rates in Jinhu Lake and Yangtze River water samples (consistent with ICP-OES results). This work provides a promising strategy for designing magnetic MOF-derived composites for high-performance environmental Pb2+ monitoring.
