This review article provides the recent progress in the electrochemical CO₂ reduction reaction by understanding and tuning catalyst–electrolyte interfaces.

Electrochemical processes coupling carbon dioxide reduction reactions with organic oxidation reactions are promising techniques for producing clean chemicals and utilizing renewable energy. However, assessments of the economics of the coupling technology remain questionable due to diverse product combinations and significant process design variability. Here, we report a technoeconomic analysis of electrochemical carbon dioxide reduction reaction–organic oxidation reaction coproduction via conceptual process design and thereby propose potential economic combinations. We first develop a fully automated process synthesis framework to guide process simulations, which are then employed to predict the levelized costs of chemicals. We then identify the global sensitivity of current density, Faraday efficiency, and overpotential across 295 electrochemical coproduction processes to both understand and predict the levelized costs of chemicals at various technology levels. The analysis highlights the promise that coupling the carbon dioxide reduction reaction with the value-added organic oxidation reaction can secure significant economic feasibility.

Carbon capture and utilization technology has been studied for its practical ability to reduce CO₂ emissions and enable economical chemical production. The main challenge of this technology is that a large amount of thermal energy must be provided to supply high-purity CO₂ and purify the product. Herein, we propose a new concept called reaction swing absorption, which produces synthesis gas (syngas) with net-zero CO₂ emission through direct electrochemical CO₂ reduction in a newly proposed amine solution, triethylamine. Experimental investigations show high CO₂ absorption rates (>84%) of triethylamine from low CO₂ concentrated flue gas. In addition, the CO Faradaic efficiency in a triethylamine supplied membrane electrode assembly electrolyzer is approximately 30% (@−200 mA cm⁻²), twice higher than those in conventional alkanolamine solvents. Based on the experimental results and rigorous process modeling, we reveal that reaction swing absorption produces high pressure syngas at a reasonable cost with negligible CO₂ emissions. This system provides a fundamental solution for the CO₂ crossover and low system stability of electrochemical CO₂ reduction.

Membrane electrode assembly (MEA) cells incorporating Cu catalysts are effective for generating C₂₊ chemicals via the CO₂ reduction reaction (CO₂RR). However, the impact of MEA configuration on the inevitable reconstruction of Cu catalysts during CO₂RR remains underexplored, despite its considerable potential to affect CO₂RR efficacy. Herein, we demonstrate that MEA cells prompt a unique reconstruction of Cu, in contrast to H-type cells, which subsequently influences CO₂RR outcomes. Utilizing three Cu-based catalysts, specifically engineered with different nanostructures, we identify contrasting selectivity trends in the production of C₂₊ chemicals between H-type and MEA cells. Operando X-ray absorption spectroscopy, alongside ex-situ analyses in both cell types, indicates that MEA cells facilitate the reduction of Cu₂O, resulting in altered Cu surfaces compared to those in H-type cells. Time-resolved CO₂RR studies, supported by Operando analysis, further highlight that significant Cu reconstruction within MEA cells is a primary factor leading to the deactivation of CO₂RR into C₂₊ chemicals.