June 18, 2019
Journal Article

Anomalously low activation energy of nanoconfined MgCO3 precipitation


Nucleation and growth of bulk magnesite (MgCO3) is well known to be kinetically inhibited at room temperature due to strong hydration of Mg2+. In operando X-ray diffraction was used to follow the temperature dependence of forsterite carbonation to magnesite within the nanoconfined space of adsorbed H2O films ~2 nm thick (~10 monolayers) and determine an apparent activation energy of only 36±6 kJ/mol. This anomalously low value suggests that Mg2+ under nanoconfinement may adopt a hydration configuration that mimics that of aqueous Ca2+, at least energetically, if not also specifically in hydration structure.

Revised: June 16, 2020 | Published: June 18, 2019


Miller Q., J. Kaszuba, H.T. Schaef, M.E. Bowden, B.P. McGrail, and K.M. Rosso. 2019. Anomalously low activation energy of nanoconfined MgCO3 precipitation. Chemical Communications 55, no. 48:6835-6837. PNNL-SA-141004. doi:10.1039/c9cc01337g