Tandem Routes for Converting Carbon Dioxide to High-Value Hydrocarbons: The Roads to Renewable Chemicals and Fuels

Upgrading CO 2 into multicarbon products (C 2+ ) through electrochemical CO 2 reduction reaction (eCO 2 RR) with renewable electricity offers a practical solution to construct a net-zero society. While much progress has been made in the direct eCO 2 RR, the challenges remain: low CO 2 conversion efficiency and selectivity to C 2, leading to high energy penalty, with little reporting on C 3+, which has higher value-added and energy density, because of complexities of reaction pathways (multistep proton-coupled electron transfer and C–C coupling processes). This perspective provides a comprehensive overview of the tandem pathway including tandem catalysts and tandem systems that can overcome the limitations of direct CO 2 electrolysis. We outline the recent advancements categorized by carbon length, from C 2 to C 4+ . While tandem catalysis covers only electrochemical reactions for C 2 production, tandem systems address the integration of electrochemical reactions with other reactions, such as thermochemical and biochemical, to expand the range of potential CO 2 upgrading products. Then, we present the opportunities and challenges of tandem routes to encourage research in this burgeoning field.