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Title: Electron transport in pure and substituted iron oxyhydroxides by small-polaron migration

Abstract

Iron oxyhydroxides (FeOOH) are common crystalline forms of iron that play a critical role in technology and the natural environment via a variety of important reduction-oxidation reactions, including electrical semiconduction as an aspect. However, a basic understanding of the electron transport properties of these systems is still lacking. We examine the electron mobility in goethite (α-FeOOH), akaganéite (β-FeOOH), and lepidocrocite (γ -FeOOH) polymorphs by means of density functional theory based (DFT+U) calculations.We show that room temperature charge transport should be dominated by the small-polaron hopping type, and that the attendant mobility should be highest for pure goethite and akaganéite. Hopping pathways through the various lattices are discussed in terms of individual electron exchange steps and rates for each. Given the usual occurrence of compositional impurities in natural iron oxyhydroxides, we also investigate the effect of common stoichiometric defects on the electron hopping activation energies such as Al and Cr substitutional cations in goethite, and Cl anions in the channels of akaganéite.

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1170451
Report Number(s):
PNNL-SA-103597
KP1702030
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics, 140(23):Article No. 234701
Country of Publication:
United States
Language:
English

Citation Formats

Alexandrov, Vitali Y., and Rosso, Kevin M. Electron transport in pure and substituted iron oxyhydroxides by small-polaron migration. United States: N. p., 2014. Web. doi:10.1063/1.4882065.
Alexandrov, Vitali Y., & Rosso, Kevin M. Electron transport in pure and substituted iron oxyhydroxides by small-polaron migration. United States. doi:10.1063/1.4882065.
Alexandrov, Vitali Y., and Rosso, Kevin M. Tue . "Electron transport in pure and substituted iron oxyhydroxides by small-polaron migration". United States. doi:10.1063/1.4882065.
@article{osti_1170451,
title = {Electron transport in pure and substituted iron oxyhydroxides by small-polaron migration},
author = {Alexandrov, Vitali Y. and Rosso, Kevin M.},
abstractNote = {Iron oxyhydroxides (FeOOH) are common crystalline forms of iron that play a critical role in technology and the natural environment via a variety of important reduction-oxidation reactions, including electrical semiconduction as an aspect. However, a basic understanding of the electron transport properties of these systems is still lacking. We examine the electron mobility in goethite (α-FeOOH), akaganéite (β-FeOOH), and lepidocrocite (γ -FeOOH) polymorphs by means of density functional theory based (DFT+U) calculations.We show that room temperature charge transport should be dominated by the small-polaron hopping type, and that the attendant mobility should be highest for pure goethite and akaganéite. Hopping pathways through the various lattices are discussed in terms of individual electron exchange steps and rates for each. Given the usual occurrence of compositional impurities in natural iron oxyhydroxides, we also investigate the effect of common stoichiometric defects on the electron hopping activation energies such as Al and Cr substitutional cations in goethite, and Cl anions in the channels of akaganéite.},
doi = {10.1063/1.4882065},
journal = {Journal of Chemical Physics, 140(23):Article No. 234701},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 12 00:00:00 EDT 2014},
month = {Tue Aug 12 00:00:00 EDT 2014}
}