Electrochemical conversion of CO2 into valuable chemicals and fuels is widely regarded as an essential pillar in the global effort to mitigate climate change and achieve carbon neutrality. However, traditional CO2 electrolysis methods, especially those utilizing alkaline or neutral electrolytes, have suffered debilitating drawbacks that have significantly hampered industrial scalability. The key challenges include salt precipitation within the electrolyzer and the notorious crossover of carbonate ions through the membrane, leading to CO2 loss and decreased energy efficiency. Such issues have capped performance and durability, rendering many technological promises unrealizable on commercial scales.

The recently published study, led by a team of chemists and chemical engineers, addresses these challenges by methodically engineering an alkaline polymer layer to coat the proton-exchange membrane. This catalytic innovation is grounded in comprehensive finite element simulations that guided the synthesis of polymers with a high density of quaternary ammonium groups. These groups play a crucial role in generating an enriched environment of hydroxide ions (OH–) near the catalyst’s electric double layer, fundamentally altering the membrane interface’s ionic dynamics.

By incorporating these ammonium-functionalized polymers, the research team succeeded in modulating the local electric field at the catalyst surface, which in turn significantly enhances CO2 adsorption. This enhancement is pivotal: increased CO2 adsorption facilitates more efficient electrochemical reduction reactions. Concurrently, the enriched hydroxide ion concentration improves interfacial ionic conductivity, minimizing resistive losses that typically plague CO2 electrolyzers. Together, these effects contribute to a decisive leap forward in overall system performance.

Crucially, the use of pure water feed, as opposed to conventional alkaline electrolytes, eliminates the sources of salt that typically precipitate and clog electrolyzer components. Salt precipitation has long been a fundamental barrier to continuous operation, forcing frequent maintenance and operational downtime in industrial settings. The design introduced here circumvents this by ensuring that salt formation is minimized or completely prevented, dramatically extending device lifetime and operational stability.

The performance metrics of this alkaline polymer-coated PEM system are unprecedented. The electrolyzer achieved an impressive single-pass CO2 conversion rate of 62.4%, indicating that a substantial majority of the input CO2 is chemically transformed in a single transit through the electrolyzer. This figure far surpasses previous benchmarks for PEM-based CO2 reduction systems. Furthermore, the energy efficiency reached 39.0%, highlighting how the system converts electrical power into chemical energy with minimal losses.

Equally noteworthy is the electrolyzer’s CO2 utilization efficiency, which hovers around 80%. This means that of all the CO2 fed into the system, nearly four-fifths is effectively converted rather than being lost or wasted—an extraordinary feat that translates directly into reduced operational costs and improved sustainability metrics. The team reported stable operation at a current density of 200 mA cm–2 for an extended period of 260 hours. Such stability is vital for industrial-scale applications where uninterrupted, long-term functioning is non-negotiable.

Beyond lab-scale demonstrations, scalability remains a critical hurdle for CO2 electrolyzers. The research group tackled this by developing a stack comprising six membrane electrode assemblies (MEAs), each with an active area of 100 cm². At a combined current of 70 A, this scaled-up system produced carbon monoxide (CO) at a maximum rate exceeding 2,000 ml per minute. This production rate is competitive with—and in some cases superior to—existing industrial CO2 reduction platforms, signaling the near-readiness of this technology for commercial deployment.

The implications of this work extend beyond improved electrolyzer performance to broader industrial and environmental impact. Efficient and scalable CO2 electrolysis technologies are central to closing the carbon loop, transforming waste CO2 into carbon-neutral or even carbon-negative chemical feedstocks. The alkaline polymer layer-coated PEM electrolyzer facilitates this vision by delivering practical solutions to enduring technical bottlenecks, thus accelerating the timeline for sustainable carbon conversion.

The innovative approach of employing a polymer layer enriched with quaternary ammonium groups appears to open new avenues for further material optimization. Fine-tuning polymer composition and layer thickness could potentially improve interfacial electric fields and ion transport properties even further. Additionally, integrating this electrolyzer design with renewable energy sources could yield fully green production chains for fuels and chemicals, propelling the clean energy transition.

Notably, this work bridges a significant knowledge gap in the understanding of interface electrochemistry at CO2 reduction catalysts. The modulation of the catalyst electric double layer by tailored polymer coatings offers a new conceptual framework for enhancing catalytic activity and selectivity. This insight is likely to inspire similar strategies across other electrochemical technologies, including water splitting and nitrogen fixation.

Furthermore, the success demonstrated with pure water feedstock points to potential advantages in simplifying system design and reducing operational complexity. Avoiding corrosive alkaline electrolytes not only mitigates material degradation but also improves safety and lowers maintenance burdens. These characteristics are particularly attractive for deployment in decentralized or modular CO2 conversion units.

The demonstration of continuous operation over 260 hours represents a significant leap toward meeting industrial durability requirements. Long operational lifetimes without degradation ensure that electrolyzers can be economically viable and competitive with traditional chemical synthesis routes. This aspect elevates the alkaline polymer layer-coated PEM electrolyzer from a laboratory curiosity to a genuine contender for real-world carbon management.

Finally, the system’s high current density operation at industrially relevant scales provides compelling evidence of its practical utility. Reaching 200 mA cm–2 and 70 A in stack configurations demonstrates that the technology transcends theoretical promise and can meet the rigorous demands of commercial applications. The team’s achievement establishes a new performance benchmark for CO2 electrolysis technologies worldwide.

In conclusion, this pioneering research marks a critical milestone in CO2 electrochemical conversion by overcoming fundamental challenges of salt precipitation, carbonate crossover, and low CO2 conversion efficiency. The combination of innovative polymer chemistry, membrane engineering, and practical scaling ushers in a new era for sustainable carbon utilization technologies. As industries seek viable solutions to the climate crisis, innovations like this alkaline polymer layer-coated PEM electrolyzer offer a hopeful blueprint for transforming captured CO2 into valuable resources—cleanly, efficiently, and at scale.

Subject of Research:
Electrochemical CO2 conversion and proton-exchange membrane electrolyzers.

Article Title:
Co-electrolysis of CO2 and H2O in an alkaline polymer layer-coated proton-exchange-membrane electrolyzer.

Article References:
Song, Y., Guo, X., Fu, Y. et al. Co-electrolysis of CO2 and H2O in an alkaline polymer layer-coated proton-exchange-membrane electrolyzer. Nat Chem Eng (2026). https://doi.org/10.1038/s44286-026-00381-4

Image Credits:
AI Generated

DOI:
https://doi.org/10.1038/s44286-026-00381-4

Green hydrogen, produced by splitting water molecules into hydrogen and oxygen via electrolysis powered by renewable energy sources, stands as a crucial vector in the global fight against climate change. However, current hydrogen production technologies face persistent challenges, particularly related to the reliance on costly precious metals and complex electrode architectures. Traditional systems conventionally require separate catalysts optimized independently for HER and OER, leading to increased material costs and engineering complexity. Additionally, the use of polymer binders to affix catalysts to electrodes often undermines electrical conductivity and long-term durability, limiting the practicality of these systems for continuous operation.

Addressing these significant drawbacks, the KIST team led by Dr. Na Jongbeom and Dr. Kim Jong Min has pioneered a technique that harnesses the exceptional catalytic capabilities of single-atom iridium dispersed uniformly on a manganese-nickel layered double hydroxide (LDH) matrix enhanced with phytic acid. This molecular anchoring agent enables atomic-scale precision in the immobilization of iridium atoms, effectively maximizing the active surface area while drastically reducing precious metal usage to less than 1.5% compared to conventional catalysts. This approach transcends traditional bulk metal catalysts by resembling an even distribution of fine sand grains rather than singular large chunks, vastly improving catalytic efficiency.

Critically, these isolated iridium atoms serve as highly active centers for the hydrogen evolution reaction. Their interaction with the Mn-Ni phytate support not only promotes efficient hydrogen production but simultaneously optimizes the oxygen evolution reaction occurring predominantly at the nickel-based sites. This bifunctional catalytic behavior is a remarkable feat, demonstrating balanced reactivity conducive to both half-reactions of water splitting within a single material system. The synergy between single-atom iridium and the transition metal support fundamentally challenges and advances existing catalyst design paradigms.

Beyond catalyst composition, the research tackles electrode architecture innovation. The team developed a binder-free electrode fabrication method by growing the catalytic material directly on the electrode substrate. This eliminates the need for polymer binders, thereby enhancing electrical conductivity and mitigating catalyst detachment during prolonged operation. Such a structural evolution is vital for ensuring durability under real-world operating conditions, affording stable performance over extensive periods without significant degradation.

Performance evaluations reveal that the ‘all-in-one’ single-atom catalyst maintains exemplary activity for both HER and OER in an anion exchange membrane (AEM) water electrolysis system, sustaining continuous operation beyond 300 hours. This level of stability under demanding electrochemical conditions underscores the robustness of the catalyst architecture and its potential for practical deployment. Furthermore, the reduced iridium content not only diminishes manufacturing costs but also aligns with sustainability goals by conserving scarce precious metal resources.

This novel catalyst design embodies a convergence of atomic-level material engineering and electrochemical innovation, exemplifying the transformative potential of single-atom catalysis in energy applications. By integrating precise control over catalytic sites with strategic electrode design, the KIST team has created a platform technology that could redefine the economics and efficiency of green hydrogen production. Their work paves the way for streamlined, cost-effective electrolysis devices capable of operating with enhanced durability and reduced material demands.

Dr. Na Jongbeom emphasized the significance of this breakthrough, stating that achieving bifunctional catalytic activity on a single catalyst while simultaneously cutting precious metal usage addresses fundamental challenges in hydrogen production technology. This advancement not only promises to accelerate adoption but also provides a scalable solution supporting the broader expansion of renewable hydrogen energy infrastructures. The potential environmental and economic impact is profound, as low-cost and stable electrolyzers are critical for widespread clean hydrogen generation.

The research, published in the prestigious journal Advanced Energy Materials, represents the culmination of intensive collaborative efforts supported by Korea’s Ministry of Science and ICT and international research partnerships. Its findings contribute foundational knowledge to the field of electrocatalysis, offering insights into the design principles for high-performance, durable, and economically viable water splitting catalysts. By bridging fundamental science with practical engineering, this technology holds promise for transformative applications in sustainable energy systems worldwide.

Looking ahead, the implementation of this atomic-precision catalyst technology in commercial water electrolysis units could significantly reduce the cost barriers currently limiting green hydrogen production scale-up. The integration of bifunctional catalytic sites and binder-free electrodes marks a paradigm shift, enabling simpler manufacturing processes and superior device performance. As global efforts intensify toward carbon neutrality, such advances in electrochemical hydrogen generation are critical for achieving resilient and clean energy supply chains.

The KIST breakthrough underscores the vital role of interdisciplinary materials science and chemical engineering in addressing complex energy challenges. By meticulously tailoring atomic configurations and electrode designs, researchers are opening new frontiers in catalyst functionality and system durability. Continued development and optimization based on these principles will likely yield even more efficient and robust catalysts, propelling green hydrogen technologies toward mainstream adoption and global impact.

Subject of Research: Water electrolysis catalysis, single-atom catalysts, hydrogen evolution reaction (HER), oxygen evolution reaction (OER), green hydrogen production
Article Title: Tailored Design of Iridium Single Atoms on Mn―Ni-Phytate with Robust Bifunctionality for Enhanced Anion Exchange Membrane Water Electrolysis
News Publication Date: January 14, 2026
Web References: http://dx.doi.org/10.1002/aenm.202506645
References: Published in Advanced Energy Materials (IF: 26.0)
Image Credits: Korea Institute of Science and Technology

Keywords

Green hydrogen, water electrolysis, single-atom catalyst, iridium, manganese-nickel layered double hydroxide, bifunctional catalyst, hydrogen evolution reaction, oxygen evolution reaction, anion exchange membrane, binder-free electrode, atomic-level precision, sustainable energy technology

As global CO₂ emissions reach unprecedented levels amid the accelerating challenges of climate change, the urgency for effective technologies to recycle this greenhouse gas intensifies. Among the various strategies to valorize CO₂, transforming it directly into energy-dense, valuable chemicals like alcohols has long been viewed as a promising avenue. Yet, achieving efficient, selective conversion to liquid C₃+ (three or more carbon atoms) compounds remains elusive due to the inherent complexities in catalysis, reaction intermediates stability, and energy efficiency.

The team, led by Professor Jaeyoung Lee along with Drs. Minjun Choi and Sooan Bae, has developed a phosphorus-rich copper catalyst system integrated within a membrane-electrode assembly, which includes a complementary nickel–iron oxidation catalyst. This configuration enables selective formaldehyde condensation reactions during the electrochemical reduction of CO₂, culminating in a highly efficient production of allyl alcohol. Impressively, the system attains a Faraday efficiency of 66.9%, an approximately fourfold improvement over previous technologies, which have struggled to surpass 15%.

One of the principal technical challenges addressed by the researchers is the facilitation of C–C bond formation during CO₂ conversion. Conventional approaches predominantly operate via carbon monoxide intermediates, which complicate the synthesis of higher molecular weight products. In contrast, the GIST team’s method uniquely navigates a novel reaction mechanism, promoting the formation of C–C bonds during the transformation of formate to formaldehyde intermediates. This shift in pathway not only enhances selectivity and yield but also stabilizes reactive species that typically prove transient and elusive in electrocatalytic environments.

Accomplishing such a leap in selectivity requires a catalyst with exceptional surface properties and chemical affinity. By integrating copper phosphide (CuP₂) into the electrode architecture, the catalyst exhibits a phosphorus-rich surface that effectively stabilizes reaction intermediates necessary for allyl alcohol synthesis. The synergy between the copper-phosphorus active sites and the nickel–iron layer optimizes electron transfer, minimizes side reactions, and suppresses undesired byproducts, thereby concentrating the electrochemical energy towards the target molecule.

Beyond efficiency, the reported technology also sets new records in current density and production rates. The electrochemical system operates at a partial current density of 735.4 mA cm⁻² and produces allyl alcohol at an unprecedented rate of 1643 μmol cm⁻² h⁻¹. These metrics highlight the method’s scalability potential, making it a promising candidate for industrial deployment. The ability to sustain high current densities while maintaining selectivity and production output is critical for transitioning from laboratory prototypes to commercial-scale CO₂ valorization technologies.

Allyl alcohol itself is an industrially vital compound with wide-ranging applications spanning the manufacture of plastics, adhesives, fragrances, and sterilizers. Currently, its production relies heavily on petroleum-based processes that are energy intensive and environmentally taxing. The GIST team’s electrochemical approach not only offers a sustainable alternative by leveraging waste CO₂ as a feedstock but also could catalyze a paradigm shift in chemical manufacturing, fostering carbon-neutral supply chains and reducing reliance on fossil resources.

This innovative CO₂-to-allyl alcohol technology further distinguishes itself through its liquid product output. Unlike gaseous fuels or products, liquids like allyl alcohol are inherently easier to store, transport, and integrate into existing industrial infrastructures. This practicality enhances the commercial appeal of the technology and aligns closely with broader goals to implement circular carbon economies where captured CO₂ is seamlessly converted into market-ready chemicals.

The researchers underscore that the development is not merely a technical achievement but also a foundational step toward transformative industrial applications. Professor Lee emphasizes that this technology could create new business opportunities across traditionally high-emission sectors such as coal, petrochemicals, and steel, helping them meet tightening environmental regulations through scalable, science-driven carbon recycling.

While the results are promising, the team acknowledges that further work is needed to realize continuous-flow operation and integrate zero-gap membrane-electrode assemblies for industrial-scale production. Dr. Choi highlights the need to refine the system for durability and sustainability to pave the way for broad adoption. Ultimately, combining such advances could significantly reduce global dependency on fossil fuels, accelerating the transition toward a greener energy and chemical landscape.

The breakthrough reflects not only a sophisticated understanding of electrochemistry and catalysis but also innovative design at the material and systems level. By pushing beyond the traditional focus on single- or two-carbon products (C₁ and C₂), this research broadens the horizon for CO₂ valorization, emphasizing the generation of more complex, higher-value molecules that meet industrial demands while aligning with climate objectives.

Published in Nature Catalysis on May 22, 2025, this study represents a milestone in carbon dioxide electroreduction research, combining novel catalyst chemistry, innovative reaction pathways, and impressive electrochemical performance metrics. The work stands as a testament to interdisciplinary collaboration and visionary research underpinned by cutting-edge materials science and chemical engineering.

As the world grapples with environmental imperatives and energy transitions, such breakthroughs ignite optimism for sustainable technologies capable of closing the carbon loop. The GIST team’s achievement signals a new chapter in electrochemical CO₂ utilization, inspiring further exploration into catalysis and reactor engineering to unlock the full potential of carbon recycling for future generations.

Subject of Research:
Not applicable

Article Title:
Selective formaldehyde condensation on phosphorus-rich copper catalyst to produce liquid C3+ chemicals in electrocatalytic CO2 reduction

News Publication Date:
22-May-2025

Web References:
http://dx.doi.org/10.1038/s41929-025-01341-6

References:
DOI: 10.1038/s41929-025-01341-6

Image Credits:
Prof. Jaeyoung Lee

Keywords

Chemical engineering, Environmental management, Pollution, Natural resources conservation, Environmental engineering, Carbon compounds, Chemical compounds, Engineering, Applied sciences and engineering, Physical sciences