In a groundbreaking study, a team led by Petra Fromme, Paul V. Galvin Professor at Arizona State University’s School of Molecular Sciences (SMS) and Director of the Biodesign Institute’s Center for Applied Structural Discovery, has made significant strides toward enhancing the capability of materials used in moisture-driven DAC technology. This cutting-edge approach harnesses humidity changes to capture and release CO₂ with minimal energy input, representing a sustainable alternative to conventional carbon capture systems. Fromme’s multidisciplinary team undertook a thorough structural investigation of two commercially available charged polymers, Fumasep FAA-3 and IRA-900, seeking to unravel the relationship between their molecular architecture and carbon capture performance.

Unlike traditional DAC methods that often rely heavily on heat or chemical reactions, moisture-swing capture exploits natural humidity fluctuations to reversibly adsorb and release CO₂. This low-energy method offers a promising route to scale carbon capture without the prohibitive energy penalties associated with sorbent regeneration. To unlock the full potential of this technology, researchers must understand how polymeric sorbents’ internal structures affect water and CO₂ transport and adsorption kinetics. To this end, the ASU team employed a suite of advanced characterization techniques to probe the materials across spatial scales—from atomic-level frameworks to macroscopic porosity.

Through X-ray diffraction, small- and wide-angle X-ray scattering (SAXS/WAXS), atomic force microscopy (AFM), focused ion beam scanning electron microscopy (FIB-SEM), and transmission electron microscopy (TEM), the researchers generated a comprehensive structural profile of these charged polymers. The combination of these methods enabled the delineation of molecular ordering, pore architecture, and hydration dynamics, offering unprecedented insight into how subtle physical features govern sorbent behavior during moisture-swing cycles. Alongside these imaging modalities, functional studies measured CO₂ adsorption and desorption capacities under variable humidity conditions, directly linking structural attributes to macroscopic performance.

The comparative analysis revealed that both FAA-3 and IRA-900 exhibited similar water uptake and release characteristics, indicating that hydration is primarily influenced by their molecular structures rather than pore size. However, critical differences emerged in carbon capture performance: IRA-900’s larger and more open pore network facilitated faster and greater CO₂ adsorption, underscoring the role of pore architecture in enhancing sorption kinetics. Furthermore, IRA-900’s higher density of ionic charge sites contributed to its superior capture efficiency by providing more active locations for CO₂ binding.

Surface analyses further elucidated the presence of structural features such as clustering, porosity, and swelling phenomena within these polymers, all of which influence their dynamic behavior in humid environments. The interplay of these factors modulates the sorbent’s ability to adsorb CO₂ during dry conditions and release it upon moisture exposure, encapsulating the mechanics of the moisture-swing process. By linking these nanoscale observations to macroscopic uptake capacities, the study lays a foundation for rational materials design aimed at optimizing both energy use and capture rates.

This research not only advances fundamental understanding of moisture-driven DAC materials but also bridges critical gaps toward practical deployment of low-energy carbon capture technologies. The insights gained from this comprehensive structural characterization empower scientists to tailor polymers at the molecular and architectural levels, thereby improving sorbent durability, selectivity, and scalability. Such advancements are imperative in meeting global carbon reduction targets and combating climate change within economically viable frameworks.

Petra Fromme and her collaborators emphasize that the ability to visualize and quantify molecular order, pore connectivity, and hydration behavior through integrated X-ray and electron microscopy techniques represents a quantum leap in DAC material science. The multidimensional perspective provided by this approach enables the dissection of complex phenomena underlying moisture-swing adsorption mechanisms, transforming empirical observations into actionable design principles. This synergy between structural analysis and functional testing opens new avenues toward next-generation sorbents with unprecedented performance metrics.

First author Gayathri Yogaganeshan, a doctoral researcher in Fromme’s group, highlights the urgent environmental relevance of this work: “Our investigation into these charged polymers targets the core challenge of extracting CO₂ from ambient air with minimal energy input. Moisture-swing DAC represents a scalable carbon removal technology that could complement existing carbon management strategies, offering hope for sustainable atmospheric remediation.” Their collaborative paper, recently published in Materials Today Chemistry, showcases this transformative study conducted at the intersection of polymer chemistry, materials engineering, and environmental science.

Many current carbon dioxide mitigation strategies focus on sequestration or biological remediation, including reforestation, soil carbon management, mineral carbonation, and bioenergy with carbon capture and storage (BECCS). However, each approach faces inherent limitations related to permanence, scalability, and land-use conflicts. Direct Air Capture circumvents some of these issues by actively extracting CO₂ from dispersed sources, but its widespread adoption hinges on innovations that minimize energetic costs. The findings from ASU’s interdisciplinary team mark a pivotal contribution toward identifying practical, low-energy materials capable of cyclic CO₂ capture and release.

The comprehensive methodology adopted by the researchers, intertwining detailed structural characterization with sorption trials under controlled humidity, underscores the complexity of moisture-swing DAC systems. It also affirms the critical balance required between molecular-scale features—such as charge site placement and polymer chain ordering—and macroscale morphological traits including pore size distribution and connectivity. By unraveling these intertwined factors, the study offers a holistic portrait of how tailored polymeric sorbents can be optimized for heightened CO₂ uptake rates and capacities.

Moving forward, these insights enable the strategic engineering of enhanced charged polymers and composite materials that marry functional precision with manufacturing viability. The implications extend beyond DAC alone, influencing allied fields like gas separation, humidity control, and energy storage where moisture-responsive materials are invaluable. As the climate challenge grows ever more urgent, such pioneering research paves the way for scalable carbon removal technologies poised to transform atmospheric chemistry and stabilize Earth’s environmental future.

This study exemplifies the power of convergent research combining molecular science, materials design, and environmental technology. As direct air capture gains momentum as a realistic climate intervention, innovations rooted in fundamental structural understanding will be crucial for achieving breakthroughs in efficiency and cost-effectiveness. The collaborative work of Petra Fromme, Gayathri Yogaganeshan, and their colleagues thus represents a beacon of progress, illuminating the path toward sustainable, energy-conscious carbon capture solutions capable of mitigating the planet’s carbon crisis.

Subject of Research:
Not applicable

Article Title:
Comprehensive structural characterization of charged polymers involved in moisture-driven direct air capture

News Publication Date:
6-Mar-2026

Web References:
https://doi.org/10.1016/j.mtchem.2026.103465

Keywords:
Direct air capture, carbon dioxide removal, moisture-swing adsorption, charged polymers, Fumasep FAA-3, IRA-900, X-ray diffraction, electron microscopy, pore architecture, molecular structure, hydration dynamics, low-energy carbon capture

Carbon nanotubes have long fascinated scientists and engineers as extraordinary materials with immense potential applications, ranging from electronics to energy storage and environmental remediation. Among their many touted capabilities is their capacity to adsorb and capture gases, including CO₂. However, the practical application of SWCNTs in carbon capture has been historically limited by their inherently closed end structures. These “caps” act like sealed tubes, restricting access to their inner hollow channels where surface area—and thus adsorption potential—could be maximized.

The team at Skoltech tackled this challenge head-on by devising an elegant one-step thermal treatment. Essentially, they subjected the SWCNTs to controlled heating at 400 degrees Celsius in ambient air for a duration of four hours. This straightforward “baking” process has profound consequences: it oxidizes residual catalyst particles found on the nanotubes and simultaneously combusts the carbonaceous end caps, effectively opening access to the nanotubes’ inner surfaces.

This method not only doubles the available specific surface area of the SWCNTs—from an initial 448 square meters per gram to an impressive 858 square meters per gram—but also preserves the structural integrity and dispersibility of the nanotubes. Unlike many chemical purification methods prone to causing nanotube bundling and loss of accessible surface sites, this thermal approach maintains an expansive and reactive surface that is directly exposed to CO₂ molecules.

The increased accessibility leads to remarkable enhancements in CO₂ capture performance. Dynamic breakthrough adsorption experiments performed by the researchers reveal an uptake capacity of 5.0 millimoles per gram of thermally treated SWCNTs. This represents an 85% improvement compared to untreated samples, a quantum leap that could make these materials viable candidates in real-world carbon capture applications.

Crucially, the study doesn’t just stop at experimental results. Through an insightful blend of Monte-Carlo simulations and geometric modeling, the team elucidates the precise nature of the interactions between CO₂ molecules and the nanotube surfaces. Their findings confirm that the “opened” nanotube channels provide energetically favorable adsorption sites, dramatically increasing the effective trapping of CO₂ at the nanoscale. This combined theoretical and experimental approach strengthens the robustness of their conclusions and opens pathways for further optimization.

The significance of this work extends far beyond academic curiosity. Developing cost-effective, scalable, and efficient carbon capture materials is a critical cornerstone of global strategies to mitigate climate change. By simplifying the modification process for SWCNTs—arguably one of the most promising nanomaterials in environmental technology—Skoltech’s research offers an accessible manufacturing blueprint that can be integrated into industrial workflows. This is especially relevant for industries looking to reduce their carbon footprint without incurring exorbitant costs associated with complex chemical processing or energy-intensive purification.

Furthermore, this innovation contributes to closing the gap between nanoscale material science breakthroughs and practical technologies. Achieving high-performance carbon capture often involves trade-offs between surface area, accessibility, and material stability. The Skoltech thermal treatment uniquely reconciles these factors by enabling high surface area realization without sacrificing the structural and functional advantages of SWCNTs.

Given the urgency of climate change mitigation, the ability to “turn up the heat” and unlock the latent potential within raw nanocarbon materials represents a crucial advancement. The research heralds a versatile, streamlined approach that could be adapted and scaled for a variety of carbon capture systems, including those integrated into power plants, industrial exhaust streams, and possibly even portable filtration devices.

It’s also a leap forward in sustainable material design philosophy. Opting for an ambient air thermal treatment avoids the environmental and safety issues tied to harsh chemical reagents. This eco-friendly methodology aligns with global green chemistry principles and reinforces the value of simplicity in high-tech solutions.

The Skoltech team’s interdisciplinary expertise in nanomaterial synthesis, surface chemistry, and computational modeling underpins this achievement. Corresponding authors Dmitry V. Krasnikov and Albert G. Nasibulin guide a research consortium that exemplifies effective collaboration between experimental and theoretical domains. Their work is sending ripples through the materials science and environmental engineering communities alike.

Skoltech has cemented its role as a crucible for cutting-edge nanomaterial innovation with tangible environmental benefits. This study is a compelling example of how fundamental research in physical sciences can lead directly to transformative technologies addressing one of humanity’s biggest challenges: climate change.

In summary, this advancement embodies how scientific elegance—using nothing more than a carefully controlled heat treatment—can unlock the tremendous potential hidden within advanced nanomaterials. As the world races to develop practical carbon capture solutions, these findings shine a spotlight on SWCNTs as viable, powerful agents for capturing CO₂ with high efficiency and scalability. The message is clear: sometimes, the key to transforming the future lies in mastering the simplest of techniques.

Subject of Research: Not applicable

Article Title: Single-step thermal treatment of single-walled carbon nanotubes for enhanced CO2 adsorption capacity

News Publication Date: 8-Jan-2026

Web References:

• Journal Carbon Research: https://link.springer.com/journal/44246
• DOI Link: http://dx.doi.org/10.1007/s44246-025-00246-0

References:
Pal, A.K., Krasnikov, D.V., Varlamova, L.A. et al. Single-step thermal treatment of single-walled carbon nanotubes for enhanced CO₂ adsorption capacity. Carbon Res. 5, 2 (2026).

Image Credits: Amit Kumar Pal, Dmitry V. Krasnikov, Liubov A. Varlamova, Konstantin K. Zamansky, Kseniya A. Litvintseva, Sergei V. Porokhin, Nikita E. Gordeev, Anastasia E. Goldt, Eugene E. Nazarov, Stanislav S. Fedotov, Pavel B. Sorokin & Albert G. Nasibulin

Keywords: Nanomaterials, Nanotechnology, Surface chemistry, Carbon nanotubes