Construction of Co3O4/Fe2O3 nanosheets on nickel foam as efficient electrocatalyst for the oxygen evolution reaction

The development of earth–abundant and high–performance electrocatalysts for oxygen evolution reaction (OER) is a very important part for electrochemical water splitting to generate cleanliness and renewable hydrogen. The preparation of heterogeneous nanostructure composite is an effective method to further improve the performance of noble–metal–free catalysts. Herein, heterogeneous nanostructure of Co3O4/Fe2O3@NF electrocatalyst for OER was fabricated by a hydrothermal method and the subsequent oxidation process. The as–prepared Co3O4/Fe2O3@NF presents a unique thin–wall cell structure. Benefiting from the thin–wall cell structure and the synergistic effect between Co3O4 and Fe2O3, as well as the three–dimensionally (3D) conductive feature of the substrate of nickel foam (NF), the Co3O4/Fe2O3@NF electrode demonstrated excellent electrocatalytic activity for OER in alkaline solution. The overpotential is 254 mV at 10 mA cm−2 current density, the Tafel slope is only 33 mV dec−1, and the electrode also retained good stability of 24 h at the current density of 20 mA cm−2. Compared with pristine Co3O4/Fe2O3 (η10 = 493 mV), Co3O4@NF (η10 = 350 mV) and Fe2O3@NF (η10 = 378 mV), the Co3O4/Fe2O3@NF electrode displayed obviously enhanced electrocatalytic performance.