A Cu coordination polymer featuring hybrid sites of open Cu sites and N-heterocyclic carbenes demonstrates superior performance for ampere-level acetylene semihydrogenation. The polymeric catalyst achieves 83.3% Faradaic efficiency of ethylene at −1.0 A cm⁻² in pure acetylene feed and maintains stable operation with coal-derived acetylene (15%) for 200 h, advancing sustainable ethylene production in membrane electrode assembly systems.

Abstract

Electrocatalytic acetylene semihydrogenation in membrane electrode assembly systems promises a sustainable pathway for ethylene production, yet faces challenges in catalyst performance and durability. Herein, we developed a Cu coordination polymer with hybrid sites that synergistically integrate open Cu sites and N-heterocyclic carbenes. These hybrid sites bestow the coordination polymer with acetylene gasophilicity, hydrophobicity toward water, and readily accessible active Cu sites, which energetically facilitate acetylene absorption and vinyl intermediate formation, thereby enabling efficient ethylene production at ampere-level current densities. In a membrane electrode assembly electrolyzer with pure acetylene, this polymeric catalyst achieved high ethylene Faradaic efficiency of 93.1% at −0.5 A cm⁻² and 83.3% at −1.0 A cm⁻², with stable operation for 100 h at −0.5 A cm⁻². Notably, even with a 15% coal-derived acetylene at a flow rate of 60 standard cubic centimeters per minute, this catalyst system demonstrated 64.4% ethylene energy efficiency and durable performance over 200 h at −0.5 A. This work advances the design of highly stable and active polymeric catalysts for electrocatalytic acetylene semihydrogenation.