Bifunctional MOF‐on‐MOF‐Derived CuCo2O4 for Oxygen Evolution Reaction Electrocatalysis and Supercapacitor Electrodes

A bifunctional copper cobalt oxide derived from metal-organic frameworks was synthesized with a spinel structure and coral reef-like morphology. It showed excellent activity for the oxygen evolution reaction, with overpotential of 317 mV at 10 mA cm⁻² and Tafel slope of 49 mV dec⁻¹. As supercapacitor electrode, it delivered 75 C g⁻¹, outperforming copper and cobalt oxides significantly.

The development of high-performance electrocatalysts for oxygen evolution reaction (OER) is still a challenge to produce green hydrogen. Thus, herein, a new bifunctional metal–organic frameworks (MOF)-derived CuCo₂O₄ is obtained, applied as OER electrocatalyst and electrode for supercapacitors. All physicochemical and morphological characterization indicates the formation of a pure spinel structure CuCo₂O₄ crystalline phase and coral reef-like morphology. X-ray photoelectron spectroscopy data showed major presence of Co³⁺ and Cu⁺ ions on the surface and high concentration of oxygen vacancies. OER electrocatalytic assays conducted in alkaline medium (1.0 M KOH) show a reduced overpotential (η) of 317 mV at 10 mA cm⁻² and Tafel slope of only 49 mV dec⁻¹, besides excellent electrochemical stability up to 12 h. The material is also studied for supercapacitors applications via cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analysis. CuCo₂O₄ material presents specific capacity near 75 C g⁻¹, at least ≈2.8 times higher than pristine CuO and Co₃O₄ at 1 A g⁻¹. This results indicate the MOFs-derived CuCo₂O₄ as a promising bifunctional material for energy conversion and storage.

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