PNNL

The Science

Capturing carbon dioxide (CO₂) is a critical piece of reaching net-zero carbon emissions goals. Water-lean solvents have been previously shown to effectively capture CO₂ and new work identifies the unique chemistry possible with these solvents. Researchers observed the formation of micellar-like nano-size clusters of four solvent molecules. The inside of these clusters has an active site core, similar to enzymes, that enables the formation of CO₂-containing species by mechanisms not previously seen in carbon capture solvents. This represents a potential paradigm shift for the reactivity possible in carbon capture solvents.

The Impact

Reaching global net-zero carbon goals requires scientific innovation. This work opens a new focus in designing solvents for carbon capture. The discovery of the unique reactivities enabled by the solvent clusters can lead to new design principles that move beyond single carbon capture. The cooperativity and reactivity observed in this work may help researchers develop more effective and efficient carbon capture solvents, leading to a net-zero future.

Summary

Carbon capture, utilization, and storage is a key yet cost-intensive technology for the fight against climate change. In a combined experimental and modelling study of a single-component water-lean solvent, researchers found that CO₂ capture is accompanied by the self-assembly of reverse micelle-like tetrameric clusters in solution. This spontaneous aggregation leads to stepwise capture phenomena with highly contrasting kinetic and thermodynamic features. The emergence of well-defined supramolecular architectures displaying an H-bonded internal core, reminiscent of enzymatic active sites, enables the formation of unprecedented CO₂-containing molecular species such as carbamic acid, carbamic-anhydride, and alkoxy carbamic anhydrides. This dynamic system based on a single absorbent and CO₂ extends the scope of adducts and mechanisms observed during carbon capture. It opens the way to new materials with a higher CO₂ storage capacity and potential cooperative binding and also provides a means for carbamates to potentially act as initiators for future oligomerization or polymerization of CO₂.

Contact

David Heldebrandt, Pacific Northwest National Laboratory, david.heldebrant@pnnl.gov

Funding

French authors were supported by the LABEX iMUST of the University of Lyon (ANR-10-LABX-0064), created within the Plan France 2030 set up by the French government and managed by the French National Research Agency. American authors acknowledge support from the Department of Energy (DOE), Office of Science, Basic Energy Sciences program, Division of Chemical Sciences, Geosciences, and Biosciences. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science user facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231.