Chemical absorption using aqueous amine solutions is one of the most mature technologies for removing CO₂ from industrial exhaust gases. MEA is particularly effective because it reacts readily with CO₂, but releasing the captured gas and regenerating the solvent requires substantial heat. This energy penalty remains a major barrier to the large-scale deployment of amine-based carbon capture. Carbon materials can promote electron transfer, while metal oxides provide acidic sites that help break down CO₂-bearing species. However, systematic comparisons of carbon supports remain limited, and conventional iron and zirconium oxides may suffer from uneven pore structures and rapid deactivation. More effective catalysts must therefore combine efficient electron transfer, suitable acidity, and long-term stability.
A study (DOI: 10.48130/scm-0026-0008) published in Sustainable Carbon Materials on 10 March 2026 by Shilin Zhao's & Zhiqiang Sun's team, Central South University, reports that optimally loaded iron-carbon nanofibers reduce solvent-regeneration energy through the combined action of metal species, oxygen-containing surface groups, and acid sites.
The researchers first compared four carbon supports: carbon nanofibers (CNF), carbon nanospheres, multi-walled carbon nanotubes, and activated carbon. They saturated 200 mL of a 5 M MEA solution with CO₂ at 40 °C, added 2.5 g of catalyst, and heated the mixture to 98 °C while continuously recording CO₂ release and energy consumption. The team evaluated each material using desorption rate, total desorption capacity, relative heat load, and a combined desorption factor. CNF performed best despite having a smaller surface area than several competing materials. Relative to the catalyst-free system, it increased the amount of CO₂ released by 31.5%, reduced the relative heat load by 22.8%, and achieved a desorption factor of 1.24. The researchers then modified CNF with different amounts of iron or zirconium. The 10% Fe-CNF formulation produced the highest desorption factor, reaching 1.55 × 10⁻³ mol³/(kJ·min). Compared with untreated CNF, it raised the desorption factor by 25% while lowering relative energy consumption by 14%. Iron loadings above 15%, however, reduced performance, probably because excess metal partially blocked active sites. To explain these differences, the team characterized the catalysts using nitrogen adsorption, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, pyridine-adsorption infrared spectroscopy, and in situ Raman spectroscopy. The analyses indicated that low-valence metal species, particularly metallic iron, worked with oxygen-containing groups on CNF to facilitate electron transfer from bicarbonate. High-valence species such as Fe³⁺ and Zr⁴⁺ contributed acidic sites that promoted MEA carbamate dissociation and protonated MEA deprotonation. In situ Raman measurements further showed that 10% Fe-CNF accelerated carbamate decomposition early in the heating process. During eight reuse cycles, the catalyst displayed no appreciable decline in CO₂ desorption capacity, supporting its potential for repeated solvent regeneration.
Overall, the study shows that catalytic performance depends on more than surface area or total metal content. The balance among low- and high-valence metal species, surface oxygen groups, conductivity, and Brønsted and Lewis acid sites determines how effectively CO₂ can be released from MEA. Although further testing under industrial conditions is needed, the findings establish a useful design strategy for durable catalysts that could reduce the energy and operating costs of post-combustion carbon capture.
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References
DOI
10.48130/scm-0026-0008
Original Source URL
https://doi.org/10.48130/scm-0026-0008
Funding information
This work was financially supported by the Science and Technology Innovation Program of Hunan Province (Grant No. 2023RC3043), the Natural Science Foundation of Hunan Province (Grant No. 2025JJ50278), and the High Performance Computing Center of Central South University.
About Sustainable Carbon Materials
Sustainable Carbon Materials (e-ISSN 3070-3557) is a multidisciplinary platform for communicating advances in fundamental and applied research on carbon-based materials. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon materials around the world to deliver findings from this rapidly expanding field of science. It is a peer-reviewed, open-access journal that publishes review, original research, invited review, rapid report, perspective, commentary and correspondence papers.