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

DOI:
https://doi.org/10.1038/s41557-025-01985-8

At the heart of this innovative approach lies the concept of single-atom catalysts (SACs). These catalysts represent a groundbreaking evolution in heterogeneous catalysis, primarily due to their design focusing on atom efficiency and maximally effective site utilization. Unlike conventional catalysts, which may have complex structures featuring multiple active sites, SACs are characterized by their highly defined active sites—often consisting of just a single metal atom embedded within a suitable support material. This design not only optimizes catalytic performance but also elucidates the structure-performance relationship critical to understanding and improving TH.

The compelling appeal of SACs in the context of transfer hydrogenation can be attributed to their superior performance metrics when compared to traditional catalyst systems. Research highlights that SACs facilitate reactions by providing an ideal environment for substrate interaction, leading to enhanced reaction rates and selectivity. These attributes are particularly crucial in industrial applications where efficiency and specificity can significantly impact economic outcomes. Furthermore, the tunability of SAC structures allows researchers to manipulate specific properties, paving the way for the development of tailored catalysts that fit the demands of particular reactions or substrates.

In this review, the relationship between the architectural features of SACs and their catalytic behaviors in transfer hydrogenation reactions is thoroughly examined. The vast array of non-H2 hydrogen sources available for TH is categorized, showcasing the diverse potential of SACs to engage with various reaction mediums. Sources such as alcohols, formic acid, and amines provide numerous opportunities for the sustainable integration of hydrogenation processes across various chemical industries. The ability of SACs to efficiently utilize these hydrogen donors makes them particularly attractive for applications like fine chemical production and biofuel synthesis.

Moreover, the review outlines the corresponding synthetic strategies employed to produce the featured structures of SACs, recognizing the intricacies involved in their preparation. Methods such as atomic layer deposition, impregnation, and co-precipitation are discussed in detail, illustrating how these techniques enable the creation of well-defined metallic sites that are paramount for optimal catalytic activity. Each synthesis method presents its unique set of advantages and challenges, effectively guiding researchers toward the most suitable approach based on their targeted application and desired outcome.

Despite the significant advancements in the field, numerous challenges remain that must be navigated to fully realize the potential of SACs in transfer hydrogenation. A primary hurdle is the stability of these single-atom catalysts under reaction conditions. Many SACs exhibit a tendency to agglomerate or leach over time, which can diminish their performance. Addressing this issue necessitates an improvement in the understanding of the interactions between the metal atoms and the support materials, aiming for enhanced stability and lifespan in practical applications.

Understanding the structure-performance relationship in SACs also opens up opportunities for novel catalyst design. By incorporating various supports and modifying the surrounding chemical environment, researchers can influence the electronic and geometric factors that determine catalytic efficiency. This exploration not only fosters the possibility of improved catalysts but also empowers scientists to contribute to a more sustainable future by enabling environmentally friendly and cost-effective hydrogenation technologies.

As the need for cleaner and more efficient chemical processes grows, the implications of successful TH catalysis featuring SACs extend beyond the laboratory. The concepts of green chemistry and the drive for carbon neutrality emphasize the importance of utilizing alternative hydrogen sources to reduce reliance on fossil fuels. The progression of TH using SACs aligns with these global objectives, as it enables the creation of products with a lower environmental impact while ensuring economic viability.

In summary, the review of transfer hydrogenation with a focus on single-atom catalysts presents a promising direction for future research and industrial applications. The strategic use of SACs addresses key challenges within the field of catalysis, illustrating the potential for impactful contributions to sustainable practices. Continued exploration of these catalysts will undoubtedly unlock new pathways for hydrogenation, ultimately leading to advancements that prioritize both efficiency and ecological responsibility in chemical manufacturing.

The discussion surrounding transfer hydrogenation and its association with SACs highlights a pivotal moment in catalytic science. The intricate interplay between structure and performance in these advanced materials opens avenues for innovation that could ultimately transform various sectors reliant on chemical processes. As researchers delve deeper into the nuances of SACs and their performance in TH, we can anticipate a future where hydrogenation is synonymous with sustainability, efficiency, and economic resilience.

The commitment to addressing the identified challenges surrounding SACs and their application in transfer hydrogenation reflects the broader ambitions of the scientific community. With continued research efforts and technological advancements, the dream of a cleaner, more efficient chemical processing landscape is within reach, bolstered by the innovative use of single-atom catalysts.

To capitalize on the growing interest in transfer hydrogenation, actionable insights can be derived from the evolving landscape of SAC technology. As the field progresses, interdisciplinary collaboration will play a crucial role in harnessing the full potential of these catalytic systems. By bridging gaps across chemical engineering, materials science, and environmental science, a comprehensive approach can be formed to tackle the multifaceted challenges present in hydrogenation processes.

In conclusion, transfer hydrogenation remains at the forefront of catalytic science, offering promising avenues for developing high-performance single-atom catalysts. As researchers worldwide continue to explore the capabilities of SACs, we are likely to witness significant advancements that not only enhance traditional hydrogenation practices but also contribute to a more sustainable future in chemical production.

Subject of Research: Transfer Hydrogenation using Single-Atom Catalysts
Article Title: Transfer Hydrogenation: Revolutionizing Catalysis with Single-Atom Catalysts
News Publication Date: [Insert Date]
Web References: [Insert Link]
References: [Insert References]
Image Credits: [Insert Image Credits]

Keywords

Transfer Hydrogenation, Single-Atom Catalysts, Catalysis, Green Chemistry, Sustainable Processes, Chemical Engineering, Hydrogenation Science, Environmental Sustainability.

Catalysts have long been at the heart of chemical innovation, acting as indispensable agents that accelerate reactions under mild conditions, reduce energy consumption, and minimize waste generation. Their central role is especially pronounced when synthesizing complex molecules, where controlling the speed, selectivity, and outcome of reactions directly impacts the efficiency and environmental footprint of chemical manufacturing. Over the decades, chemists have relentlessly pursued catalyst designs that can meet the stringent requirements of modern synthetic processes—demanding specificity, sustainability, and scalability.

Enzymes, nature’s highly evolved catalysts, have emerged as exceptional candidates in this quest due to their unmatched selectivity and biocompatibility. These protein-based catalysts orchestrate countless biochemical reactions with remarkable speed and precision, often under ambient conditions that are challenging to replicate synthetically. However, harnessing enzymes for non-natural or particularly demanding chemical transformations, such as asymmetric organic synthesis involving metal-mediated pathways, has remained a formidable challenge.

The metal hydride hydrogen atom transfer (MHAT) reaction represents a fascinating and powerful catalytic method recently developed to efficiently construct complex molecular architectures. In this reaction, a metal hydride species—comprising a metal atom bonded to a hydrogen atom—effectively transfers the hydrogen atom to an unsaturated carbon double bond within an organic substrate. This transfer generates a highly reactive intermediate that subsequently undergoes bond formation to sculpt intricate molecular frameworks. MHAT’s capability to transform planar, two-dimensional molecules into stereochemically rich three-dimensional constructs makes it a transformative tool in synthetic chemistry.

Despite MHAT’s remarkable utility, achieving precise stereochemical control in these reactions remains an enduring dilemma. The issue lies in fabricating molecules with a definitive “handedness” or chirality—mirror-image structures that, while chemically identical, exhibit distinct three-dimensional arrangements. This differentiation is not merely academic; in drug development, for instance, one enantiomer (handed form) of a molecule can deliver therapeutic benefits, whereas its mirror counterpart may be inert or even harmful. Therefore, catalysts capable of directing MHAT reactions to yield exclusive enantiomers are of immense scientific and industrial value.

Addressing this intricate challenge, the University of Basel team leveraged the inherent chiral environment of a haemoprotein—a class of enzymes known for their metal-binding capabilities and biological versatility. By ingeniously reengineering the catalytic site of this enzyme, they enabled it to facilitate MHAT reactions with outstanding enantioselectivity. The unique protein scaffold not only stabilizes reactive intermediates but also enforces a stringent three-dimensional spatial arrangement, resulting in a product ratio with up to 98% dominance of a single enantiomer. Such stereocontrol is unprecedented in the context of MHAT chemistry and represents a milestone in enzyme engineering.

The implications of this research extend well beyond proving a concept. Integrating enzymatic catalysis with MHAT opens a new frontier in green chemistry by potentially reducing reliance on harsh chemical reagents and solvents, lowering energy input, and diminishing toxic by-products. The ability to selectively produce single-handed complex molecules can revolutionize the synthesis of pharmaceuticals, agrochemicals, and other value-added fine chemicals, addressing both sustainability and efficiency imperatives facing the chemical industry.

At the same time, the researchers recognize that the highly specialized nature of their engineered enzyme presents dual challenges. While its specificity ensures remarkable selectivity for a given substrate, it also means that alterations to starting materials may necessitate further enzyme modifications to maintain catalytic performance. This specificity, therefore, requires dynamic and iterative protein engineering strategies to broaden substrate scope without compromising efficiency.

Moreover, the formation of metal hydride intermediates within a biological framework currently depends on steps that could be optimized to enhance sustainability. Developing more environmentally benign methods to generate these reactive species will be a critical focus of future work, further aligning enzymatic MHAT catalysis with the principles of green chemistry.

The study represents a confluence of disciplines, merging insights from molecular biology, inorganic chemistry, and catalysis to transcend traditional synthetic limitations. It highlights the growing role of protein engineering in crafting bespoke catalysts capable of performing complex transformations, underlining the transformative potential of molecular systems engineering as a paradigm for chemical innovation.

The findings, recently published in the prestigious journal Nature, are the product of collaborative efforts led by Professor Thomas R. Ward and his team. Their pioneering work illustrates not only the power of enzyme repurposing but also charts a path toward more precise and sustainable manufacture of chiral molecules—cornerstones of countless therapeutic and industrial applications.

With this breakthrough, the boundaries of catalytic science are expanding, heralding an era where nature’s catalysts are tailored to meet the synthetic demands of humanity. As researchers continue to refine enzyme scaffolds for even broader reaction types and substrate classes, it becomes increasingly feasible to envisage a future where chemical synthesis mirrors the sophistication and efficiency of biological processes.

The University of Basel’s accomplishment sets a benchmark and invites a reimagining of synthetic strategy—one where enzyme and metal coexist harmoniously, driving forward the development of safer, cleaner, and economically viable chemical technologies. This inventive synergy is likely to inspire further explorations at the interface of biology and chemistry for years to come, reinvigorating a fundamental understanding of catalysis and molecular design.

Subject of Research: Repurposing haemoproteins to catalyze asymmetric metal hydride hydrogen atom transfer reactions for stereoselective synthesis of complex molecules.

Article Title: Repurposing haemoproteins for asymmetric metal-catalysed H atom transfer

News Publication Date: 30-Jul-2025

Web References: DOI: 10.1038/s41586-025-09308-0

Image Credits: University of Basel, Xiang Zhang

Keywords

Enzyme engineering, metal hydride hydrogen atom transfer, asymmetric catalysis, stereoselectivity, haemoprotein, green chemistry, molecular synthesis, chiral molecules, catalytic specificity, pharmaceutical synthesis, molecular systems engineering