CO2 Hydration at the Air-Water Interface: A Surface-Mediated ‘In and Out’ Mechanism

Add to your list(s) Download to your calendar using vCal

• Samuel Brookes, University of Cambridge
• Wednesday 21 May 2025, 14:30-15:00
• Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry.

If you have a question about this talk, please contact Lisa Masters.

An understanding of the CO2 + H2O hydration reaction is crucial for modeling the effects of ocean acidification, for enabling novel carbon storage solutions, and as a model process in the geosciences. While the mechanism of this reaction has been investigated extensively in the condensed phase, its mechanism at the air-water interface remains elusive, leaving uncertain the contribution that surface-adsorbed CO2 makes to the overall acidification reaction. In this study, we employ state-of-the-art machine-learned potentials to provide a molecular-level understanding of CO2 hydration at the air-water interface. We show that reaction at the interface follows a surface-mediated ‘In and Out’ mechanism: CO2 diffuses into the aqueous surface layer, reacts to form carbonic acid, and is subsequently expelled from solution. We show that this surface layer provides a bulk-like solvation environment, engendering similar modes of reactivity and near-identical free energy profiles for the bulk and interfacial processes. Our study unveils a new, unconventional reaction mechanism that underscores the dynamic nature of the molecular reaction site at the air-water interface. The similarity between bulk and interfacial profiles shows that CO2 hydration is equally as feasible under these two solvation environments and that acidification rates are likely enhanced by this additional surface contribution.

This talk is part of the Theory - Chemistry Research Interest Group series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• Department of Chemistry
• Featured lists
• Lennard-Jones Centre external
• School of Physical Sciences
• Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry

Note that ex-directory lists are not shown.