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Title: 2H and 27Al solid-state NMR study of the local environments in Al-doped 2-line ferrihydrite, goethite, and lepidocrocite

Although substitution of aluminum into iron oxides and oxyhydroxides has been extensively studied, it is difficult to obtain accurate incorporation levels. Assessing the distribution of dopants within these materials has proven especially challenging because bulk analytical techniques cannot typically determine whether dopants are substituted directly into the bulk iron oxide or oxyhydroxide phase or if they form separate, minor phase impurities. These differences have important implications for the chemistry of these iron-containing materials, which are ubiquitous in the environment. In this work, 27Al and 2H NMR experiments are performed on series of Al-substituted goethite, lepidocrocite, and 2-line ferrihydrite in order to develop an NMR method to track Al substitution. The extent of Al substitution into the structural frameworks of each compound is quantified by comparing quantitative 27Al MAS NMR results with those from elemental analysis. Magnetic measurements are performed for the goethite series to compare with NMR measurements. Static 27Al spin–echo mapping experiments are used to probe the local environments around the Al substituents, providing clear evidence that they are incorporated into the bulk iron phases. As a result, predictions of the 2H and 27Al NMR hyperfine contact shifts in Al-doped goethite and lepidocrocite, obtained from a combined first-principles andmore » empirical magnetic scaling approach, give further insight into the distribution of the dopants within these phases.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6]
  1. Stony Brook Univ., Stony Brook, NY (United States); Dong-A Univ., Busan (South Korea)
  2. Stony Brook Univ., Stony Brook, NY (United States)
  3. Univ. of Cambridge, Cambridge (United Kingdom)
  4. SUNY Binghamton, Binghamton, NY (United States)
  5. Univ. of Wisconsin, Madison, WI (United States)
  6. Stony Brook Univ., Stony Brook, NY (United States); Univ. of Cambridge, Cambridge (United Kingdom)
Publication Date:
Grant/Contract Number:
AC02-98CH10886
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 27; Journal Issue: 11; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Stony Brook Univ., Stony Brook, NY (United States); Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1344907

Kim, Jongsik, Ilott, Andrew J., Middlemiss, Derek S., Chernova, Natasha A., Pinney, Nathan, Morgan, Dane, and Grey, Clare P.. 2H and 27Al solid-state NMR study of the local environments in Al-doped 2-line ferrihydrite, goethite, and lepidocrocite. United States: N. p., Web. doi:10.1021/acs.chemmater.5b00856.
Kim, Jongsik, Ilott, Andrew J., Middlemiss, Derek S., Chernova, Natasha A., Pinney, Nathan, Morgan, Dane, & Grey, Clare P.. 2H and 27Al solid-state NMR study of the local environments in Al-doped 2-line ferrihydrite, goethite, and lepidocrocite. United States. doi:10.1021/acs.chemmater.5b00856.
Kim, Jongsik, Ilott, Andrew J., Middlemiss, Derek S., Chernova, Natasha A., Pinney, Nathan, Morgan, Dane, and Grey, Clare P.. 2015. "2H and 27Al solid-state NMR study of the local environments in Al-doped 2-line ferrihydrite, goethite, and lepidocrocite". United States. doi:10.1021/acs.chemmater.5b00856. https://www.osti.gov/servlets/purl/1344907.
@article{osti_1344907,
title = {2H and 27Al solid-state NMR study of the local environments in Al-doped 2-line ferrihydrite, goethite, and lepidocrocite},
author = {Kim, Jongsik and Ilott, Andrew J. and Middlemiss, Derek S. and Chernova, Natasha A. and Pinney, Nathan and Morgan, Dane and Grey, Clare P.},
abstractNote = {Although substitution of aluminum into iron oxides and oxyhydroxides has been extensively studied, it is difficult to obtain accurate incorporation levels. Assessing the distribution of dopants within these materials has proven especially challenging because bulk analytical techniques cannot typically determine whether dopants are substituted directly into the bulk iron oxide or oxyhydroxide phase or if they form separate, minor phase impurities. These differences have important implications for the chemistry of these iron-containing materials, which are ubiquitous in the environment. In this work, 27Al and 2H NMR experiments are performed on series of Al-substituted goethite, lepidocrocite, and 2-line ferrihydrite in order to develop an NMR method to track Al substitution. The extent of Al substitution into the structural frameworks of each compound is quantified by comparing quantitative 27Al MAS NMR results with those from elemental analysis. Magnetic measurements are performed for the goethite series to compare with NMR measurements. Static 27Al spin–echo mapping experiments are used to probe the local environments around the Al substituents, providing clear evidence that they are incorporated into the bulk iron phases. As a result, predictions of the 2H and 27Al NMR hyperfine contact shifts in Al-doped goethite and lepidocrocite, obtained from a combined first-principles and empirical magnetic scaling approach, give further insight into the distribution of the dopants within these phases.},
doi = {10.1021/acs.chemmater.5b00856},
journal = {Chemistry of Materials},
number = 11,
volume = 27,
place = {United States},
year = {2015},
month = {5}
}