Coupling of CO2 electroreduction and biomass electrooxidation: challenges, design principles, and perspectives.

Sustainable carbon management through innovative strategies is essential to address the dual crises of climate change and resource scarcity. Electrochemical CO2 reduction reaction (CO2RR) and biomass electrooxidation (BEO) represent two promising pathways for converting CO2 and renewable biomass into valuable chemicals. While previous reviews have broadly covered replacing the energy-intensive anodic oxygen evolution reaction (OER) for CO2RR, they often lack an integrated analysis of the complementary challenges and design principles for CO2RR & BEO coupling system. This review fills this gap by critically analyzing their core key limitations, notably the high energy cost of OER in CO2RR and the low economic return from the hydrogen evolution reaction (HER) in BEO; meanwhile, the design principles, e.g., potential matching, pH and product compatibility, for the couple system are proposed. Moreover, coupled systems that effectively exploit the complementary nature of CO2RR & BEO are systematically presented, including CO2RR paired with the oxidation of biomass-derived molecules and other substrates (e.g., glucose, alcohols, aldehydes, methane, chlorides, sulfides) and BEO coupled with other cathodic reductions (e.g., furfural, 4-nitrophenol). Meanwhile, their compatibility in term of potential, pH and product were analyzed and compared. Finally, future research directions are outlined, with emphasis on innovative catalysts design, system-level optimization, and scalable implementation. This work provides a focused perspective on advancing sustainable resource utilization through electrochemical coupling.