Synthesis and characterizations of ZIF-8/GO and ZIF-8/rGO composites for highly sensitive detection of Cu²⁺ ions

In this paper, we describe the synthesis and characterization of ZIF-8/GO and ZIF-8/rGO composites for electrochemical sensing of Cu²⁺ ions. To prepare the composites, GO or rGO was dispersed in a solution of Zn(NO₃)₂·6H₂O and 2-methylimidazole in anhydrous methanol. We used several techniques, such as XRD, Raman spectroscopy, and FESEM, to investigate the structural, morphological, and chemical properties of the materials. The composites exhibited peaks corresponding to both ZIF-8 and GO or rGO in the XRD patterns. For the electrochemical analysis of Cu2+ ions, we employed a disposable screen-printed electrode (SPE). The ZIF-8/GO composite-based Cu²⁺ ion sensor exhibited superior sensitivity of 362.5 mA.µM^-1.cm^-2 and LOD of 9 µm to Cu²⁺ ions in a comparison with ZIF-8/rGO (224.28 mA.µM^-1.cm^-2) and ZIF-8 (102.9 mA.µM^-1.cm^-2) alone. Our results demonstrate the potential of ZIF-8/GO composites as a promising material for electrochemical sensing applications.