Design Strategies for Stable and Active Co-Based Electrocatalysts in Acidic Oxygen Evolution Reaction

Proton exchange membrane water electrolysis (PEMWE) offers several advantages over alkaline water electrolysis, including a more compact design, faster response time, lower ohmic losses, and higher gas purity. However, the harsh acidic conditions required for PEMWE have led to the use of noble metal-based electrocatalysts for the oxygen evolution reaction (OER), particularly ruthenium (Ru) and iridium (Ir), which are both scarce and costly. In recent years, significant progress has been made in the development of cobalt (Co)-based electrocatalysts, which exhibit promising performance in acidic OER, providing a more sustainable and cost-effective alternative to precious metals. This review provides a comprehensive summary, classification, and discussion of the latest Co-based catalysts for acidic OER. Key insights into the fundamental mechanisms of the OER, as well as the relationships between catalytic activity and stability, are highlighted. Additionally, the review examines the various synthesis strategies for Co-based catalysts and highlights methods to enhance their OER performance. Finally, the review concludes by addressing the current challenges in the field and offering insights into future research directions aimed at developing high-performance Co-based materials for efficient OER under acidic conditions.