Electrochemical study of the Cu²⁺ sensor based on ZIF-67/MWCNTs/Nafion

In this work, a ZIF-67/MWCNTs/Nafion sensor platform was constructed based on the good adsorption capacity of ZIF-67, the electrical conductivity of multiwalled carbon nanotubes (MWCNTs), and the excellent chemical stability of Nafion for the detection of Cu²⁺ in water. Meanwhile, the modified materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET-specific surface area test, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier-transform infrared spectrometry (FTIR). Cyclic voltammetry (CV), electrochemical impedance (EIS), and square wave stripping voltammetry (SWSV) electrochemical methods were used to perform applied test studies on ZIF-67/MWCNTs/Nafion/GCE. The results show that ZIF-67/MWCNTs/Nafion/GCE has high sensitivity (57.5 μA/μM) and a low limit of detection (15.0 nM) for the electrochemical detection of Cu²⁺ ions in an electrochemical sensing system. It has high adsorption selectivity for Cu²⁺, and the recovery of Cu²⁺ in real water reached 98.6–103%. The modified electrode has good repeatability, reproducibility, anti-interference, and stability, which means this sensing platform can be practically applied to the detection of domestic water.