Structural, Electrochemical, and Supercapacitor Characterization of Double Metal Oxides Doped Within ZIF-8 Composites

This study investigates the application of double metal oxide zinc ferrite (ZnFe2O3) doped within zeolitic imidazolate framework-8 (ZIF-8) composites for structural, electrochemical, and supercapacitor characterization. The structural characterization has been carried out using XRD, FTIR, DTA, UV-VIS, and HRTEM. By incorporating ZnFe2O3, significant enhancements in the structural integrity and morphology of the ZIF-8 matrices have been achieved, with a decrease in the average crystallite size by about 23%. At 500 °C, the DTA analysis indicated that the weight loss associated with ZnFe2O3 decreased by approximately 5%. The estimated Eg values are 3.08 eV and 3.28 eV for ZIF-8 and ZIF-8@ZnFe2O3, respectively. Regarding the electrochemical performance of the ZIF-8@ZnFe2O3, the anodic peak current density is approximately 0.0025 A (at around 0.5 V), at a scan rate of 10 mV/s. The peak current values increase more rapidly, by about 41%, with increasing scan rate when ZnFe2O3 is present, indicating a synergistic effect between the ZIF-8 and ZnFe2O3 components. The high observed current density peak at 0.03 V can be attributed to the Fe2+/Fe3+ redox couple, facilitated by the ZnFe2O3 component. The ZnFe2O3 addition enhances the electrochemical activity of ZIF-8, leading to increased peak current values at various scan rates. This suggests that the ZnFe2O3 may facilitate charge transfer or improve the conductivity of the material.