Multifunctional Engineering and Active Sites Regulation of Covalent Organic Frameworks for Efficient Electrocatalytic Acetylene Hydrogenation to Ethylene

Electrocatalytic acetylene reduction (EAR) provides a promising pathway to achieve acetylene (C₂H₂) semihydrogenation to produce ethylene (C₂H₄). However, it remains a great challenge to make the electrocatalysts fulfill key factors including C₂H₂ enrichment, activation, electron transfer, and active sites simultaneously for efficient EAR. Covalent organic frameworks (COFs) have attracted much attention due to the advantages of the introduction of functional groups and efficient electron transfer by covalent linkage, which will be a promising electrocatalyst for EAR, while no studies have achieved EAR by using COFs. In this work, we rationally designed a series of multifunctional COF electrocatalysts encompassing the above functions and achieved efficient EAR by regulating the type of active sites. Among them, the EA-16FCuPc COF exhibits an ∼100% Faraday efficiency of C₂H₂-to-C₂H₄ in pure C₂H₂ flow. Significantly, for industrial crude C₂H₄ flow containing 1 × 10⁴ ppm of C₂H₂, EA-16FCuPc COF could produce polymer-grade C₂H₄ containing only 2.1 ppm of C₂H₂ impurity and continuously produce pure C₂H₄ streams (C₂H₂ < 10 ppm) at large space velocity. This work explored the design of COFs to integrate multiple functions onto one catalyst and achieve efficient EAR, demonstrating the great potential of multifunctional COFs in the field of electrocatalysis.