Highly sensitive electrochemical sensor for lead ions based on Bi-MOF/conducting polymer composites

Herein, conductive polyaniline (PANI) was chemically polymerized on the surface of a bismuth-based metal-organic framework (Bi-MOF) to form conductive PANI@Bi-MOF composites. FT-IR and PXRD measurements verified the successful production of PANI@Bi-MOF, whereas SEM, TEM, and EDAX mapping demonstrated that PANI was uniformly coated on the surface of Bi-MOF. The resulting PANI@Bi-MOF composites were characterized by cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS), then used to develop a sensitive electrochemical sensor for the detection of lead ions based on differential pulse anodic stripping voltammetry (DPASV). The developed sensor possessed a low detection limit of 0.0108 μg/L and a wide linear detection range (0.025–20 μg/L). The sensor was successfully applied for the detection of Pb²⁺ in real water samples, showing negligible response to other coexisting metal cations. This work offers a feasible approach for detecting Pb²⁺ ions in water.