A Review of Electrochemical-Biological Coupling Systems for CO2 Valorization: Catalytic Fundamentals, System Integration, and Industrial Outlook.

To support dual-carbon goals and address the limitations of conventional CO2 valorization technologies, this review summarizes recent advances in electrochemical-biological coupling systems for high-value CO2 utilization, with emphasis on catalytic fundamentals, system integration, and industrial prospects. We discuss catalyst and reactor design for CO2 electroreduction to C1/C2 liquid platform molecules, particularly formate, acetate, and methanol, and their subsequent biological conversion. The review further examines metabolic and engineering strategies by which microbial cell factories assimilate electro-generated substrates to produce high-value compounds, including amino acids, organic acids, polysaccharides, and polyhydroxybutyrate (PHB). Key bottlenecks in electrocatalyst stability, gas diffusion electrodes, reactor operation, carbonate accumulation, cathode flooding, metabolic compatibility, flux matching, and system-level coupling are analyzed. We also highlight the roles of artificial intelligence, multiscale modeling, smart control, techno-economic analysis, and life-cycle assessment in accelerating scale-up and industrial translation. Overall, electrochemical-biological coupling provides a "capture-convert-valorize" route that integrates renewable-electricity-driven electrocatalysis with biomanufacturing, enabling CO2 conversion into multicarbon, value-added products and offering a promising platform for sustainable carbon recycling and carbon-negative manufacturing.