Development of an electrochemical sensor based on <scp>LDH</scp> for the highly sensitive determination of Pb ²⁺

Abstract Zinc‐aluminum layered double hydroxide (ZnAl‐LDH) was successfully synthesized via a one‐step coprecipitation method and directly modified onto a glassy carbon electrode (GCE) to construct a ZnAl‐LDH/GCE working electrode. A systematic comparison of MAl‐LDH formed from different divalent metal sources (M = Zn 2+ , Ca 2+ , Mg 2+ , Ni 2+ ) revealed that ZnAl‐LDH exhibited the most favorable morphology and performance. Despite the inherently poor conductivity of LDH materials, the specific interaction between metal hydroxyl groups (−M‐OH) on the ZnAl‐LDH surface and Pb 2+ significantly enhanced the electrochemical response signal for Pb 2+ . Optimization of key parameters including supporting electrolyte, pH, enrichment potential, and time established optimal detection conditions at pH = 5.0 in 0.1 mol/L acetic acid–sodium acetate (ABS) buffer, with enrichment at −0.9 V for 230 s. Under these conditions, the electrochemical sensor demonstrated outstanding analytical performance for Pb 2+ detection: a linear range of 0.4–25 μmol/L, a detection limit as low as 0.031 μmol/L (S/N = 3), along with excellent selectivity, stability, and reproducibility. Satisfactory recovery rates achieved in real‐water samples further validate the sensor's practical application potential in environmental monitoring.