Optimization strategies on the advanced engineering of Co-based nanomaterials for electrochemical oxygen evolution

Abstract The sluggish oxygen evolution reaction (OER) kinetics is the critical problem that hinders the practical applications of metal-air batteries and water electrolyzers. Co-based nanomaterials with high catalytic activity, rich abundance and low-cost, are deemed as one of the most promising electrocatalysts for OER. In this review, we present an overview of the recent developed optimization strategies on the advanced engineering and controllable synthesis of Co-based nanomaterials for OER. The mechanism and performance merits for the OER are introduced first, and then the different material optimization concepts and strategies including elemental doping, defect engineering, morphology regulation and control, heterostructure engineering, and single-atom catalyst design, are reviewed to provide a deep insight into the relationship between composition, structure and performance. The practical applications of Co-based OER catalysts in water electrolysis are further highlighted in detail. And the current challenges and prospect towards the further development of Co-based electrocatalysts are finally summarized.