Realizing high performance bifunctional energy storage devices and electrocatalytic water splitting catalysts through regulated interface engineering of ZnCo2O4@Co3O4 nanosheets

Abstract

The development and optimization of electrocatalysts is one of the key points to reduce the energy barrier of electrocatalytic water splitting and improve the kinetics of electrocatalytic reactions. It is necessary to develop low-cost, high-performance electrocatalysts with large-scale application prospects. In order to solve this problem, hybrid structured ZnCo₂O₄@Co₃O₄ nanowires are successfully synthesized through hydrothermal synthesis and electrodeposition. As electrocatalysts for water splitting, ZnCo₂O₄@Co₃O₄ can reach a current density of 50 mA cm⁻² at an overpotential of 278 mV for the OER and 166 mV@−10 mA cm⁻² for the HER, which could be higher than that of single ZnCo₂O₄ and Co₃O₄. At the same time, ZnCo₂O₄@Co₃O₄ samples also exhibit a cell voltage of 1.67 V at a high current density of 50 mA cm⁻² and superior durability for 50 h. The fabricated product also showcases a specific capacitance of 1316 F g⁻¹ at 1 A g⁻¹. Additionally, the assembled device attains a maximum energy density of 47.3 W h kg⁻¹ at a power density of 1126 W kg⁻¹. Furthermore, density functional theory (DFT) calculation further confirms that the heterostructure can significantly promote Gibbs free energy for hydrogen adsorption. And the significant increase in the density of total states (DOS) also enhances the catalytic activity for the HER.