Advances in Electrochemistry for CO2 Capture and Conversion

Electrochemistry is emerging as a transformative approach to both capture and convert carbon dioxide, offering routes that can be powered directly by renewable electricity and that avoid the large thermal penalties of traditional solvent regeneration. Recent advances span materials, cell design, and system architectures that together are shrinking energy requirements, improving selectivity for valuable products, and enabling new integrated processes that combine capture and conversion in tighter, more efficient loops.

At the materials level, catalyst discovery has been a primary driver of progress. Nanostructured catalysts, oxide-derived surfaces, and single-atom active sites have all produced significant gains in selectivity and activity. Copper remains the most versatile metal for producing multi-carbon products, and innovations such as highly roughened Cu surfaces, oxide-derived Cu, and tandem catalyst architectures have raised faradaic efficiencies for C2+ products while lowering overpotentials. For two-electron products, tin, bismuth and indium-based catalysts continue to deliver high selectivity to formate, and silver and gold catalysts are leading choices for efficient CO production at commercially relevant current densities.

Equally important are advances in electrode and cell design that allow high reactant availability and effective product removal. Gas diffusion electrodes (GDEs) enable direct contact between gaseous CO2 and a thin catalyst layer, supporting current densities of hundreds of milliamps per square centimeter--levels necessary for economically meaningful production. Membrane electrode assemblies (MEAs) and zero-gap electrolyzers reduce ohmic losses and enable compact, scalable cell stacks. Meanwhile, bipolar membranes and novel ion-conducting separators allow designers to manage local pH and ion transport, mitigating carbonate formation and crossover which have been persistent efficiency drains in aqueous systems.

A major technical hurdle has been CO2 loss to carbonate in alkaline electrolytes and the associated crossover of carbonate or bicarbonate ions, which both reduce single-pass conversion and increase energy intensity. Progress has come from operating in neutral or acidic environments using specially engineered catalysts, adopting membrane chemistries that block crossover, and developing flow configurations that minimize CO2 consumption by side reactions. Solid oxide electrolysis cells (SOECs) operating at high temperature provide an alternative that bypasses some aqueous challenges by converting CO2 in oxide-ion-conducting ceramics to CO or syngas with high energy efficiency, though they introduce materials and durability trade-offs.

Beyond conversion catalysts, significant work is underway to reimagine the capture step itself through electrochemical means. Electro-swing adsorption and redox-active capture materials--such as quinone-functionalized electrodes and electrochemically regenerated amine systems--can capture CO2 at ambient conditions and release it upon application of an electrical potential rather than heat. These approaches can dramatically reduce the energy penalty of capture and enable modular devices that couple capture and conversion in the same or adjacent electrochemical units, reducing the need for compression and transport of concentrated CO2 streams.

Integration of capture and conversion is an emerging architecture with compelling benefits: captured CO2 can be fed directly to electrolyzers in gaseous or dissolved form, reducing handling steps and capital costs. Clever reactor designs now incorporate capture media that desorb CO2 at concentrations suitable for electroreduction, or use membrane configurations that concentrate CO2 at the catalyst interface. Such tandem systems can be particularly attractive for point-source capture at industrial stacks or for direct air capture when paired with highly selective conversion catalysts and energy sources.

System-level improvements have also targeted energy efficiency and product value. Paired electrolysis--where a valuable anodic reaction replaces the oxygen evolution reaction--can lower overall cell voltage while producing useful co-products, improving economics. Coupling CO2 electrolysis with intermittently available renewable electricity requires fast-reacting and resilient systems; research on catalyst stability, transient operation, and dynamic control strategies is making electrolyzers more compatible with variable power inputs from wind and solar.

Technoeconomic analyses indicate clear performance targets for commercialization: electrolyzers must reach high current densities (>200-300 mA cm-2), maintain low cell voltages (ideally under ~3 V for many target products), and achieve high faradaic efficiencies toward a single product or a narrow product slate to minimize costly separations. Catalyst longevity--measured in thousands of hours--along with tolerance to impurities in flue gas or ambient air, are essential to reduce maintenance and replacement costs.

Despite strong progress, challenges remain. Scaling lab-scale demonstrations to industrial throughput exposes issues in mass transport, heat management, and long-term material degradation. Product separation, especially for liquid fuels and oxygenates produced at low concentrations, adds cost and complexity. Life-cycle assessments must account for the carbon intensity of electricity, materials manufacturing, and system construction to ensure genuine climate benefit. Nevertheless, the pace of materials innovation, improved cell architectures, and systems thinking that integrates capture with conversion point toward competitive pathways for electrochemical CO2 utilization in the coming decade.

In summary, advances in electrochemistry are carving multiple routes to decarbonization: efficient direct conversion of concentrated CO2 to chemicals and fuels, electrochemically enabled low-energy capture, and tightly integrated processes that combine both steps. With continued progress in catalyst design, membrane science, and system integration--and with the parallel decarbonization of the electricity supply--electrochemical CO2 capture and conversion could become a cornerstone technology for a circular carbon economy.