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.