Recent advances in upgrading CO2 to C3+ products via electrochemical and complementary engineering

Abstract

Upgrading CO2 to various carbon-containing products through renewable electrochemical routes offers a promising solution to achieve a “Net Zero” and circular economy. Multicarbon C3+ products are especially energy-rich and economically valuable. However, due to the diverse possibilities of C–C coupling and the complexities of reaction pathways, the efficient and selective electrochemical upcycling of CO2 to C3+ products remains a tremendous challenge. Summarizing the latest advances in generating C3+ products from CO2, this review focuses on both key material development and process design in electrochemical and complementary engineering approaches. For the methodologies involving only electrochemical reactions, we categorize them based on the catalysts adopted, summarizing the specific design strategies and mechanistic understandings on copper and non-copper catalysts, respectively. To further improve the efficiency of C3+ synthesis, the concept of “electrochemical + X” is introduced. “X” herein refers to a complementary sector to direct CO2 electrolysis, encompassing the homogeneous non-electrocatalytic reactions in a one-pot electrochemical process and the sequential thermochemical or biological processes after electrochemical CO2 conversion. Lastly, we discuss the challenges of pure electrochemical as well as “electrochemical + X” approaches and outline promising future directions. We believe that this review contains a comprehensive summary on the means to optimize for C3+ compounds, and can motivate researchers to develop innovative strategies to further enhance C3+ production efficiency, paving the road towards the ultimate renewable-driven chemical industries.