Atomic-scale study of calcite nucleation in calcium oxide

Rémy Besson (1) , Loïc Favergeon (2, 3, 4)

1 UMET - Unité Matériaux et Transformations - UMR 8207
2 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
3 PRESSIC-ENSMSE - Procédés et REactivité des Systèmes Solide-gaz, Instrumentation et Capteurs
4 LGF-ENSMSE - Laboratoire Georges Friedel

In spite of its wide use, the properties of the CaO/CaCO₃ system are still far from being understood, especially the mechanisms underlying the transition between both phases. To investigate this issue, important in practice for storage devices, we employ first-principles atomic-scale simulations of the solid-gas interactions between CO₂ and CaO, by considering insertion of CO₂ within the subsurface, in configurations characteristic of calcite surface nucleation. Comparing the (001) and (111) surfaces demonstrates that nucleation should be strongly surface-selective, with a sharp preference for (111), and an important role of the CO₂ arrangement in the surface layer. To interpret these results, especially the important structural instabilities detected, we investigate the elastic properties of coherent CaO/CaCO₃ layered systems. This reveals the special role played by the (111) interface orientation and confirms the behavior detected at the atomic scale. From our study, we propose a mechanism for calcite nucleation as well as a plausible explanation for the degradation of performances crippling the CaO-based devices used for CO₂ storage.

Mots clés: atomic-scale simulations; solid-gas interactions; CaO/CaCO₃ system; storage devices . calcite surface nucleation

Domaines: Génie des procédés

Rémy Besson, Loïc Favergeon. Atomic-scale study of calcite nucleation in calcium oxide. Journal of Physical Chemistry C, 2013, 117 (17), pp.8813-8821. ⟨10.1021/jp4002252⟩. ⟨hal-00833817⟩