Constructing Cu⁰/Cu⁺ interfaces on Cu-based MOF derivatives to promote the adsorption stability of intermediates in the process of CO₂ electroreduction to C₂ products

Utilizing electrocatalysis to convert CO₂ into high-value industrial raw materials can not only effectively reduce CO₂ emissions but also achieve a closed carbon cycle. This method holds great potential for addressing global warming and alleviating the fossil fuel crisis. Here, we report a novel electrocatalyst for CO₂ reduction composed of a composite material derived from Cu-MOF74 and Cu₂O, synthesized under the regulation of an appropriate amount of KOH. The research results indicate that the unique Cu⁰/Cu⁺ interface in Cu-MOF74/Cu₂O-350 enhances the adsorption of reaction intermediates, providing more active sites for CO₂ reduction. Additionally, the moderate carbonization during the thermal treatment process increases conductivity and enriches the electrochemical active surface area, accelerating the charge transfer rate. Consequently, this composite exhibits excellent CO₂ reduction performance. At −1.3 V vs. RHE, the Faraday efficiency (FE) for C₂H₄ production reached up to 32.48%, which was significantly higher than that of pure Cu₂O-350 (9.25%) and Cu-MOF74-350 (15.52%). Even after 6 hours of reaction, the FE for C₂H₄ remained above 24.52%, reflecting its good stability. Furthermore, we utilized in situ infrared spectroscopy to study the key intermediates of the relevant reduction products, inferring the possible reaction pathways for the formation of HCOOH and C₂H₄. This study provides a simple synthesis method for the preparation of high-selectivity MOF-derived composite catalysts for the electrocatalytic reduction of CO₂ to value-added chemicals. © 2024 The Royal Society of Chemistry.