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

• DOI: 10.48550/arxiv.2502.08348
• Publication Date: 2025-02-12
• Authors: Samuel G. H. Brookes; Venkat Kapil; Angelos Michaelides; Christoph Schran
• Keywords: Interface (matter)

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