Capturing carbon dioxide (CO 2 ) before it reaches the atmosphere is a key strategy for reducing greenhouse gas emissions. Even though carbon capture technologies have existed for decades, their widespread adoption has been slow for a straightforward reason: most of them are expensive and inefficient. For example, aqueous amine scrubbing, which is the most common industrial method, requires heating large volumes of liquid above 100 °C to release captured CO 2 and reset the system for reuse. These energy demands translate directly into operating costs, making large-scale deployment challenging.
Carbon-based solid adsorbents have emerged as a promising alternative. These solid, inexpensive materials with large surface area can bind CO 2 and then release it with less heat under low temperature, especially when featuring nitrogen-containing functional groups. Unfortunately, while the performance benefits of these functional groups are apparent, standard synthesis methods can only deposit them randomly and in mixed configurations, making it difficult to know which specific arrangement actually drives efficient performance and why.
Against this backdrop, a research team led by Associate Professor Yasuhiro Yamada from the Graduate School of Engineering and Associate Professor Tomonori Ohba from the Graduate School of Science at Chiba University, Japan, tackled this problem. Their work reports the synthesis and thorough characterization of a new class of carbon materials called 'viciazites,' which contain a carefully controlled configuration of nitrogen groups in adjacent positions. The paper, published online in the journal Carbon on February 27, 2026, was co-authored by Mr. Kota Kondo, also from Chiba University.
The team synthesized three distinct viciazites, each carrying a different type of adjacent nitrogen pairing. To introduce adjacent primary amine groups (–NH 2 groups), they carbonized a compound called coronene at high temperature, then treated the material with bromine and finally with ammonia gas. This three-step process produced adjacent –NH 2 groups with 76% selectivity, meaning that the vast majority of introduced nitrogen ended up in the target configuration. The other two materials were made using different precursors: one carrying adjacent pyrrolic nitrogen was synthesized at 82% selectivity, and the other with adjacent pyridinic nitrogen was synthesized at 60% selectivity.
All three materials were coated onto activated carbon fibers to create practical adsorbent samples. The researchers used several techniques, including nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and computational modeling to confirm that the introduced nitrogen groups were indeed positioned next to each other in an adjacent manner and not scattered randomly.
Performance tests showed clear differences between the three configurations. The materials with adjacent –NH 2 groups and adjacent pyrrolic nitrogen both outperformed untreated carbon fibers in CO 2 uptake, while adjacent pyridinic nitrogen groups showed little benefit. The most striking result was observed with desorption, which is the process of releasing the captured CO 2 to regenerate the material. " Performance evaluation revealed that in carbon materials where NH 2 groups are introduced adjacently, most of the adsorbed CO 2 desorbs at temperatures below 60 °C. By combining this property with industrial waste heat, it may be possible to achieve efficient CO 2 capture processes with substantially reduced operating costs ," highlights Dr. Yamada. Additionally, the pyrrolic nitrogen-containing material, though releasing CO 2 at a higher temperature, may prove more durable in the long run owing to the superior chemical stability of that functional group.
Overall, by showing that adjacent nitrogen configurations can be built deliberately and reproducibly, this study establishes a promising design framework for the next generation of carbon capture materials. " Our motivation is to contribute to the future society and to utilize our recently developed carbon materials with controlled structures. This work provides validated pathways to synthesize designer nitrogen-doped carbon materials, offering the molecular-level control essential for developing next-generation, cost-effective, and advanced CO 2 capture technologies ," concludes Dr. Yamada. The researchers also note that viciazite materials may find uses beyond CO 2 capture, such as adsorbents for metal ions and catalysts, given the precise and tunable nature of their surface chemistry.
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Reference:
Authors: Kota Kondo 1 , Ayane Uchizono 2 , Lizhi Pu 1 , Itsuki Takahashi 3 , Ryoshin Suzuki 1 , Sota Nakamura 1 , Kai Kan 4 , Kazuma Gotoh 4 , Tetsuro Soejima 5 , Satoshi Sato 1 , Tomonori Ohba 3 , and Yasuhiro Yamada 1
Affiliations: (1) Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University; (2) Faculty of Engineering, Chiba University; (3) Graduate School of Science, Chiba University; (4) Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST); (5) Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University
DOI: 10.1016/j.carbon.2026.121405
About Associate Professor Yasuhiro Yamada from Chiba University
Dr. Yasuhiro Yamada obtained his PhD in February 2008 from The State University of New York at Buffalo. He currently serves at the Graduate School of Engineering, Chiba University. He conducts research on structurally controlled carbon materials, focusing on developing techniques for structural control and analysis and unraveling the mysteries of high-performance carbon materials. He has published more than 150 papers to his name.
About Associate Professor Tomonori Ohba from Chiba University
Dr. Tomonori Ohba obtained his PhD in March 2002 from Chiba University. He currently serves at the Graduate School of Science, Chiba University. He conducts research on the molecular systems at the interfaces of nanoscale materials and nanoscale material chemistry. He has published more than 214 articles to his name.
Funding:
This work was supported by Mukai Science and Technology Foundation, Japan Society for the Promotion of Science (JSPS KAKENHI Grant Number JP24K01251), and the "Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM)" of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) under Grant Number JPMXP1225JI0008.
Carbon
Experimental study
Not applicable
Viciazites: Carbon Materials with Adjacent Nitrogen Functionalities for Advanced CO2 Capture
27-Feb-2026
The authors declare that they do not have any conflict of interest.