Large-Scale Synthesis of Fe-Doped Amorphous Cobalt Oxide Electrocatalysts at Room Temperature for the Oxygen Evolution Reaction

Reasonable optimization of the crystal structure and composite is an effective way to enhance the electrocatalytic activity of transition metal oxides. Herein, we report a strategy to fabricate Fe-doped amorphous CoOx (a-CoyFezOx) as an oxygen evolution reaction (OER) catalyst by a facile reduction reaction at room temperature. In a 1 M KOH electrolyte, the optimized a-Co2.5Fe0.5Ox catalyst shows the best OER activity. It only requires a 280 mV overpotential to achieve a current density of 10 mA cm–2 with a Tafel slope of 39.9 mV dec–1, which is even better than that of a commercial IrO2 catalyst. This high activity can be ascribed to the combined merits of the amorphous structure and the doped Fe element. The amorphous structure can enlarge the electrochemically accessible surface area and offer more active sites, while the Fe doped into the amorphous CoOx material can not only form the Fe site to promote the adsorption of intermediates during the OER process but also optimize the electronic structure of neighboring Co sites to enhance the OER activity. This work provides a strategy for rational design and large-scale synthesis of the transition metal oxide electrocatalysts to enhance the OER performance.