Precious-Metal-Free Co-Fe-O/rGO Synergetic Electrocatalysts for Oxygen Evolution Reaction by a Facile Hydrothermal Route

Abundant iron group metal oxides and their composites possess great potential in the application of electrochemical energy storage and conversion. In this work, we obtained Co–Fe–O composites/reduced graphene oxides (CFO/rGO) hybrid structures, engineered their compositions, phase, and structures by a facile hydrothermal route, and studied their composition‐dependent activity for electrochemical oxygen evolution reaction (OER) in alkaline media. It is found that synergetic effects bring a clear decrease in overpotential and Tafel slope for CFO/rGO catalysts in comparison with monometallic composition/rGO catalysts. OER charge‐transfer resistance is significantly reduced after Fe addition, indicating that the reaction barriers of CFO/rGO are reduced. The optimal CFO/rGO with Co–Fe ratio of 2:1 was identified. Our results on the synergetic effects of CFO/rGO enrich the understanding of iron‐group composites for electrocatalytic applications. No bling here! Precious‐metal‐free Co–Fe–O composites/rGO hybrid structures were obtained by a facile hydrothermal route. They exhibited apparent composition‐dependent activity for the electrochemical oxygen evolution reaction. It is found that synergetic effects contribute a significant decrease of overpotential and Tafel slope for composite catalysts.