Electrodeposition of stacked CFZN metallic oxide nanosheets as high-performance bifunctional electrocatalyst for HER and supercapacitor

Abstract

• CuO/CuFe₂O₄/Zn catalyst grown on 3D-Ni via electrodeposition and trapping. • Achieved 258 F g⁻¹ specific capacitance at 0.5 A g⁻¹ for CFZN supercapacitor. • CFZN showed 40 mV overpotential and 53 mV dec⁻¹ Tafel slope for alkaline HER. Electrocatalytic water splitting and supercapacitor technologies are vital for sustainable energy storage and conversion, providing effective alternatives to fossil fuels in addressing global warming. To advance eco-friendly electrochemical devices, it is essential to develop highly efficient and durable electrocatalysts, focusing on simple and controllable fabrication methods. In this study, we synthesized stacked CuO/CuFe₂O₄/Zn catalysts on a 3D-Ni substrate, termed CFZN, using a simple electrodeposition and trapping strategy. These electrodes aim to improve the activity and long-term stability of supercapacitors (SCs) and the hydrogen evolution reaction (HER). The CFZN nanosheets electrode achieved a remarkable capacitance of 258 F g⁻¹ at 0.5 A g⁻¹ in a two-electrode system. The SC fabricated with these nanosheets presented an energy density of 14.52 Wh kg⁻¹ and a capacitance retention of 87.11 %. The CFZN electrocatalyst exhibited impressive performance with overpotentials of just 40 mV and Tafel slope values of 53 mV dec⁻¹ for HER in an alkaline environment. Additionally, density functional theory (DFT) calculations provided insights into the electronic structure through density of states (DOS) analysis and evaluated the Gibbs free energy of intermediate hydrogen adsorption. This theoretical analysis reinforces the material's potential for high-performance electrochemical applications.