ZIF-8@CoFe2O4 as a highly efficient bifunctional electrocatalyst for the methanol oxidation and oxygen evolution reactions

Abstract

Developing low-cost, highly active, and stable electrocatalysts is essential to realize various renewable energy storage and conversion systems. In particular, zeolite imidazole frameworks (ZIFs) and ZIF-based composites have garnered considerable interest for energy-related applications. In this study, ZIF-8@CoFe₂O₄ composites are synthesized using a simple and facile method. Three ZIF-8@CoFe₂O₄ composites named ZCFO-1, ZCFO-2, and ZCFO-3, synthesized with varying concentrations of CoFe₂O₄ (10, 20, and 40.0 mg, respectively), are used. The synthesized ZCFO-composites are used as catalysts in the electrocatalytic methanol oxidation reaction (MOR) and oxygen evolution reaction (OER). In the MOR, the ZCFO-1 electrocatalyst exhibits a higher current density and stability for more than 6 h than other electrocatalysts. In addition, the synthesized electrocatalysts are tested for the OER, and ZCFO-1 exhibits a lower overpotential of 330 mV and a Tafel slope of 84 mV dec⁻¹. The synthesized ZCFO-1 electrocatalyst exhibits higher activity and stability for both the MOR and OER, thus suggesting that it is an alternative to noble metal electrocatalysts.