Emerging covalent organic frameworks tailored materials for electrocatalysis

Covalent organic frameworks (COFs) are an emerging type of porous crystalline polymers with tunable nanopore size, high accessible surface area, predesigned building units, abundant active sites, devisable chain structures, and programmable topological architectures. These collective characteristics are essential in creating high-efficiency electrocatalysts for energy conversion and fuel generation in metal-air batteries and fuel cells. Recent years have witnessed considerable advances in rational design and controllable fabricate of COF-based electrocatalysts for oxygen reduction, oxygen evolution, hydrogen evolution, and CO2 reduction reactions. In this review, engineering strategies of COFs toward electrocatalysts are first summarized and given particular attention, highlighting their influence on intrinsic electrocatalytic performance. A systematic overview of the fundamental principles behind specific electrocatalysis reactions is then performed. Significant breakthroughs of COFs and their derivatives are presented in detail with an emphasis on the relationship between the molecular structures of COFs and their electrocatalytic performance. Lastly, current challenges and future perspectives on tailoring COFs for high-performance electrocatalysts are discussed. This review aims to identify general guidelines and the potential of COFs to outperform state-of-the-art electrocatalysts that use their noble metal-based counterparts.