Near 100% Conversion of Acetylene to High‐purity Ethylene at Ampere‐Level Current

Abstract Direct production of high‐purity ethylene from acetylene using renewable energy through electrocatalytic semi‐hydrogenation presents a promising alternative to traditional thermocatalytic processes. However, the low conversion of acetylene results in a significant amount of acetylene impurities in the product, necessitating additional purification steps. Herein, a tandem electrocatalytic system that integrates acetylene electrolyzer and zinc‐acetylene battery units for high‐purity ethylene production is designed. The ultrathin CuO nanoribbons with enriched oxygen vacancies (CuO_1‐x NRs) as electrocatalysts achieve a remarkable 93.2% Faradaic efficiency of ethylene at an ampere‐level current density of 1.0 A cm⁻² in an acetylene electrolyzer, and the power density reaches 3.8 mW cm⁻² in a zinc‐acetylene battery under acetylene stream. Moreover, the tandem electrocatalysis system delivers a single‐pass acetylene conversion of 99.998% and ethylene selectivity of 96.1% at a high current of 1.4 A. Experimental data and calculations demonstrate that the presence of oxygen vacancies accelerates water dissociation to produce active hydrogen atoms while preventing the over‐hydrogenation of ethylene. Furthermore, techno‐economic analysis reveals that the tandem system can dramatically reduce the overall ethylene production cost compared to the conventional thermocatalytic processes. A novel strategy for complete acetylene‐to‐ethylene conversion under mild conditions, establishing a non‐petroleum route for the production of ethylene is reported.