In‐situ Growth of a Bimetallic Cobalt‐Nickel Organic Framework on Iron Foam: Achieving the Electron Modification on a Robust Self‐supported Oxygen Evolution Electrode

Abstract As a clean energy source, hydrogen may be obtained via overall water splitting. However, the reaction is limited by the anodic oxygen evolution reaction (OER) in the catalytic field. In order to overcome the limitation in OER catalyst activity, this paper attempts to synthesize and develop a series of three‐dimensional metal‐organic frameworks (MOFs) electrocatalytic materials. The structure and morphology of bimetallic cobalt and nickel MOFs are characterized by FT‐IR, Raman, SEM, TEM, and XPS. It is found that the bimetallic cobalt and nickel MOFs have a columnar micro‐structure assembled by nanosheets. Further in‐situ growth on the iron (Fe) foam to prepare an integrated nanoarray self‐supported electrode did not significant change their micro‐structure. The obtained bimetal electrocatalysts exhibit significantly enhanced OER activity as compared to the single‐metal MOFs counterpart. The cobalt and nickel double‐doped materials in‐situ grown on Fe foam exhibited an excellent electrocatalytic activity and remarkable durability with a current density of 10 mA cm −2 in a 0.1 M KOH solution (with the overpotential of 264 mV and the Tafel slope of 54.3 mV dec −1 ). There is a significant improvement compared with the material on the glassy carbon electrode. The introduction of the bimetal species (Co and Ni) into the ordered MOFs provides a synergistic effect of the active centers resulting in an enhanced electron transfer and improved electrochemical performance. This work enriches the MOFs electrocatalytic electrode and pave the way for their practical applications.