In the relentless pursuit of sustainable chemical manufacturing, the electrochemical conversion of carbon dioxide (CO₂) and carbon monoxide (CO) into valuable hydrocarbons and oxygenates stands out as a beacon of hope. These processes promise to not only mitigate greenhouse gas emissions but also generate feedstocks and fuels essential for the chemical industry. While significant strides have been made in electroreducing CO to single-carbon (C₁) and two-carbon (C₂) products, the synthesis of three-carbon (C₃) compounds remains an intricate and elusive challenge. A recent pioneering study published in Nature Chemistry now sheds light on unlocking this frontier by leveraging the co-electroreduction of CO and glyoxal, unveiling a pathway towards selectivity in producing C₃ products with unprecedented efficiency.
For years, researchers have focused on converting CO and CO₂ electrochemically, given CO’s role as a key intermediate in these transformations. While producing C₁ molecules such as methane or formate, and C₂ compounds like ethylene and ethanol, has witnessed rapid improvements in catalyst design and operational parameters, the generation of C₃ products—embodying higher carbon complexity and potential industrial value—lags significantly. This bottleneck arises from the complex mechanistic pathways and unfavorable energetics involved in forming carbon-carbon bonds extending beyond two units under electrochemical conditions.
The breakthrough study pivots on the hypothesis that C₃ species formation is linked intimately with the ethylene pathway but can be selectively enhanced by modifying reaction intermediates’ interactions. To interrogate this pathway, the researchers employed a strategic approach combining probe reactants and isotope-labeled CO, thereby elucidating precise mechanistic insights. Their experiments conclusively demonstrate that introducing glyoxal—a simple, reactive aldehyde—into the reaction milieu notably promotes the formation of C₃ products while concurrently suppressing the competing formation of acetate and ethanol, two common C₂ byproducts.
What stands out strikingly in these findings is that while glyoxal catalyzes C₃ product formation, it itself remains scarcely consumed throughout the process. Such behavior suggests that glyoxal’s role transcends being a mere reactant; it functions quasi-catalytically by altering the adsorption dynamics and surface chemistry on the catalyst interface. This subtle yet profound effect manifests in decreased coverage of CO-derived intermediates adsorbed on the catalyst surfaces, as revealed through advanced in situ spectroscopic techniques. The suppression of CO* species coverage offers a new tactical lever in steering product selectivity toward more complex hydrocarbons.
Notably, the researchers further examined the interplay between the surface coverage of adsorbed CO species and the presence of hydroxide ions (OH⁻) in the electrolyte. Their reaction order studies revealed that higher surface concentrations of both CO and OH⁻ correlated strongly with suppression of ethylene formation, favoring the emergence of C₃ products instead. This insight recognizes the nuanced role of electrolyte composition and local pH environment in dictating catalytic outcomes, highlighting that control over reaction microenvironment is as crucial as catalyst architecture itself.
Combining these dual insights—the glyoxal-induced modulation of CO* coverage and the OH⁻-rich conditions that suppress undesired ethylene pathways—enabled the team to engineer conditions that maximize selectivity for C₃ products. This synergistic effect resulted in reported Faradaic efficiencies reaching 53%, a remarkable achievement in the realm of electrochemical CO reduction reactions. Such efficiency not only sets a new benchmark but also underscores the feasibility of steering catalytic pathways toward desired multicarbon products through co-reactant and electrolyte engineering.
Delving deeper into mechanistic aspects, the study leveraged isotope-labeling to track carbon atom origins within products, solidifying the evidence that C₃ compounds arise directly from coupling between CO and glyoxal-derived intermediates. This mechanistic confirmation dispels ambiguities about product formation routes and lends credibility to the idea that controlled co-electroreduction strategies can profoundly alter reaction landscapes to favor specific outcomes.
These revelations hold transformative implications for catalyst design paradigms. Traditionally, electrocatalysts for CO and CO₂ reduction have prioritized metal composition and surface morphology to enhance activity and selectivity. However, this work elucidates how introducing ancillary reactants such as glyoxal and optimizing electrolyte conditions can complement and even surpass traditional approaches by modulating surface chemistry and reaction kinetics in previously unexploited ways. This paradigm shift may open new avenues for tailoring the product spectrum simply by chemical environment tuning.
Furthermore, the suppression of common C₂ byproducts such as acetate and ethanol, often considered unavoidable side reactions, marks a crucial advance in leaner, more efficient conversion processes. This reduction in side product formation not only improves the overall atom economy of the reaction but also simplifies downstream separation and purification, aligning with industrial scalability requirements.
From a sustainability perspective, the ability to selectively convert CO and derivative carbon species into higher-order hydrocarbons aligns strikingly with emerging circular carbon economy goals. Instead of relying on fossil-based feedstocks, catalytic electrochemical routes fueled by renewable electricity can unlock cyclic utilization of waste carbon species into chemicals and fuels. Achieving high selectivity for valuable C₃ products enhances the economic viability and practical attractiveness of such processes.
The study’s use of sophisticated spectroelectrochemical methods, combining operando infrared and Raman spectroscopy, exemplifies the critical role of advanced analytical tools in deciphering complex reaction mechanisms at the electrode interfaces. Such tools empower researchers to visualize dynamic changes in adsorbed species and intermediate formations in real-time, paving the way for rational catalyst and process improvements driven by empirical data.
Looking ahead, these findings provide a compelling blueprint for the rational design of novel electrocatalysts tailored specifically for multicarbon product generation. Future research might explore analogous co-reactants beyond glyoxal or engineer catalytic surfaces that inherently favor the beneficial adsorption dynamics observed here. Similarly, electrolyte engineering approaches to precisely modulate local pH, ion concentration, and polarity could further optimize product distributions.
The implications extend beyond just laboratory-scale benchmarks. Given the accelerating global push to decarbonize chemical industries and deploy CO₂ valorization technologies, breakthroughs like this one could become foundational technologies in sustainable manufacturing. Industrial implementation would require continued advancements in catalyst stability, scaling of electrochemical cells, and integration with renewable energy sources, but the conceptual framework is now robustly established.
In sum, the co-electroreduction of CO and glyoxal represents a paradigm shift in electrochemical carbon upgrading, transforming a longstanding challenge into an achievable objective. By uncovering mechanistic nuances and leveraging synergistic reaction environments, this innovative approach successfully channels carbon feedstocks toward higher-value C₃ products with exceptional selectivity and efficiency. As the chemical industry accelerates toward greener futures, such discoveries will undoubtedly catalyze transformative technological leaps on the journey from carbon waste to carbon wealth.
Subject of Research:
Electrochemical co-reduction of carbon monoxide (CO) and glyoxal to enhance selective formation of three-carbon (C₃) products.
Article Title:
Co-electroreduction of CO and glyoxal promotes C₃ products.
Article References:
Dorakhan, R., Sarkar, S., Shirzadi, E. et al. Co-electroreduction of CO and glyoxal promotes C₃ products. Nat. Chem. (2025). https://doi.org/10.1038/s41557-025-01985-8
Image Credits:
AI Generated
