UiO-66/ZIF-67/PEDOT Modified Glassy Carbon Electrode for Electrochemical Detection of Cu²⁺ and Hg²⁺ in Environmental Water

Abstract

ZIF-67 and UiO-66 are different metal-organic framework (MOFs) materials widely used in gas adsorption, energy storage, catalysis, and electrochemical sensing due to their unique pore structure and chemical properties. Here, UiO-66/ZIF-67/PEDOT material modified glassy carbon electrode was prepared, and Cu 2+ and Hg 2+ in water were detected by electrochemical method (differential pulse voltammetry). ZIF-67 grows in flakes on the surface of UIO-66, and the two formed a synergistic effect, improving the selectivity and sensitivity of the detection. In addition, by coating a PEDOT film on the surface of the binary MOF, the conductivity of the material is further enhanced, thereby greatly improving the detection sensitivity. Under the optimized deposition conditions, the material has good linearity and low detection limit for the detection of Cu 2+ in the concentration range of 1–35 μg l −1 and Hg 2+ in the concentration range of 5–40 μg l −1 . The limits of detection (LOD) were LOD(Cu) = 0.78 μg l −1 and LOD(Hg) = 0.19 μg l −1 for individual detection. When the two ions were detected at the same time, there was a good linearity for Cu 2+ , but the linear detection results for Hg 2+ were partially disordered. In addition, the sensor exhibits good anti-interference and detection stability, showing the potential for practical applications.