Nanoconfinement Facilitates Reactions of Carbon Dioxide in Supercritical Water

Abstract

The reactions of CO${}_2$ in water under extreme pressure-temperature conditions are of great importance to the carbon storage and transport below Earth's surface, which substantially affect the carbon budget in the atmosphere. We applied ab initio molecular dynamics simulations to study aqueous carbon solutions nanoconfined by graphene and stishovite (SiO${}_2$) at 10 GPa and 1000$\sim$1400 K. We found that CO${}_2$(aq) reacts more in nanoconfinement than in bulk. The stishovite-water interface makes the solutions more acidic, which shifts the chemical equilibria, and the interface chemistry also affects the reaction mechanisms. Our findings suggest that CO${}_2$(aq) in deep Earth may be more active than previously thought, and confining CO${}_2$ and water in nanopores may enhance the efficiency of mineral carbonation.

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Cited by in corpus (3)

• Raman and IR spectra of water under graphene nanoconfinement at ambient and extreme pressure-temperature conditions: a first-principles study
• Unveiling the hidden reaction kinetic network of carbon dioxide in supercritical aqueous solutions
• Formation of abiogenic hydrocarbons in supercritical fluids under Earth's upper mantle conditions