Abstract
The individual elementary reactions involved in the dissolution of a solid into solution remain mostly speculative due to a lack of direct experimental probes. In this regard, we have applied atomistic simulations to map the free-energy landscape of the dissolution of gibbsite from a step edge as a model of metal hydroxide dissolution. The overall reaction combines kink formation and kink propagation. Two individual reactions were found to be rate-limiting for kink formation, that is, the displacement of Al from a step site to a ledge adatom site and its detachment from ledge/terrace adatom sites into the solution. As a result, a pool of mobile and labile adsorbed species, or adatoms, exists before the release of Al into solution. Because of the quasi-hexagonal symmetry of gibbsite, kink site propagation can occur in multiple directions. Overall, our results will enable the development of microscopic mechanistic models of metal oxide dissolution.
Original language | English |
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Pages (from-to) | 1809-1814 |
Number of pages | 6 |
Journal | Journal of Physical Chemistry Letters |
Volume | 9 |
Issue number | 7 |
DOIs | |
State | Published - Apr 5 2018 |
Funding
This work was supported by IDREAM (Interfacial Dynamics in Radioactive Environments and Materials), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES). The research was performed using PNNL Institutional Computing at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle Memorial Institute under Contract No. DE-AC05-76RL0-1830. The authors gratefully acknowledge fruitful discussions with Xin Zhang regarding experimental observations of gibbsite dissolution and Micah Prange regarding DFT simulations setup.
Funders | Funder number |
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Energy Frontier Research Center | |
IDREAM | |
U.S. Department of Energy | |
Battelle | |
Office of Science | |
Basic Energy Sciences |