Electrochemical and dielectric analysis of multifunctional GQDs@PEG@Mg-ZnFe₂O₄ ternary nanohybrid for low-frequency electronics, water splitting, and sustainable energy storage applications

This work explores the potential of GQDs@PEG@Mg-ZnFe₂O₄ nanocomposite in water splitting and energy storage applications. The synthesized hybrid showed remarkable dielectric properties indicating its potential for low-frequency telecommunications and electronics applications. The impedance spectroscopy disclosed the contribution of grains and grain boundaries in the realization of colossal permittivity (10⁴) in GQDs@PEG@Mg-ZnFe₂O₄. Moreover, GQDs@PEG@Mg-ZnFe₂O₄ showed excellent energy storage performance, indicated by its specific capacitance of 100 Fg⁻¹ and a retention ratio of 99 % over 1000 cycles at a 1 Ag⁻¹ current density. GQDs@PEG@Mg-ZnFe₂O₄ nanohybrid also showed remarkable electrocatalytic activity, both for hydrogen evolution reaction and oxygen evolution reaction. The determined Tafel slope value was found to be 90 mVdec⁻¹ and 110 mVdec⁻¹ at a 10 mA/cm² current density, respectively. These results highlight the multifunctional nature of the GQDs@PEG@Mg-ZnFe₂O₄ nanocomposite and its potential as a versatile material to address challenges in both energy storage and conversion technologies.