Molecular Views of Mineral Carbonation: Reaction of CO<sub>2</sub> with the Wollastonite (100) Surface.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41876390.
- Also identified by DOI 10.1021/acsnano.5c19629 and PMC identifier 13063804.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The carbonation of silicate minerals is a key process in the Earth's carbon cycle and offers a promising avenue for long-term CO<sub>2</sub> sequestration. However, the atomistic mechanisms by which CO<sub>2</sub> is activated at silicate surfaces remain poorly understood, largely due to the intrinsic complexity and insulating nature of these materials. To close this gap, wollastonite (CaSiO<sub>3</sub>) is used as a model system. Noncontact atomic force microscopy (nc-AFM) with functionalized tips is combined with density functional theory (DFT) to investigate its lowest-energy (100) surface under ultrahigh vacuum (UHV). Upon cleaving the mineral in UHV, water vapor is released from the sample and spontaneously readsorbs into a previously unreported, exceptionally stable configuration. The resulting surface hydration layer promotes spontaneous CO<sub>2</sub> chemisorption and the formation of surface carbonates with negligible kinetic barriers. Our results offer atomic-scale evidence of gas-phase carbonation on a silicate mineral, revealing a water-assisted pathway for CO<sub>2</sub> capture that bypasses aqueous mineral dissolution.