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This content will become publicly available on March 26, 2019

Title: Free-Energy Landscape of the Dissolution of Gibbsite at High pH

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, in this paper 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. Finally, 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.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical Sciences Division. Physical & Computational Sciences Directorate
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Science Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 9; Journal Issue: 7; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1462840