Covalent Organic Frameworks Based Single-site Electrocatalysts for Oxygen Reduction Reaction

Single site catalysts(SSCs) are a new type of heterogeneous catalysts formed by isolated metal atoms supported on kinds of substrates. SSCs have shown great potential for energy conversion and storage in recent years, especially for oxygen reduction reactions(ORR). Typically, SSCs are confined on the substrate by strong chemical interactions, such as coordination bonds. Therefore, the surface chemical environment and porous properties of the supports are crucial to the performance of SSCs. In recent years, COFs have become excellent candidates for preparing SSCs as they can precisely assemble monomers into highly ordered crystalline porous materials with a fine structure and definite components. In this review, we not only summarize the characteristics and advantages of COFs based SSCs, but also highlight the applications of COFs constructed from different single active sites for ORR in recent years. Finally, challenges in practical application, feasible strategies and perspectives are proposed for the of COFs based SSCs.