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Title: Templating Growth of a Pseudomorphic Lepidocrocite Microshell at the Calcite–Water Interface

The growth of lepidocrocite (gamma-FeOOH) has been observed through oxidation of Fe(II) on calcite (CaCO 3). Here, we seek to understand the structural relation between lepidocrocite and the calcite substrate and its growth mechanism. The formation of iron oxyhydroxide layers having distinct morphologies was observed during the dissolution of calcite in acidic Fe(II)-rich solutions. A pseudomorphic lepidocrocite shell together with multiple iron oxyhydroxide layers encapsulated within the shell was imaged by optical and transmission X-ray microscopies. The presence of a several-nanometer-thick ordered lepidocrocite film was observed by X-ray reflectivity, with the lepidocrocite (100) plane oriented parallel to the calcite (104) surface. Lath-shaped lepidocrocite aggregates formed during the initial precipitation, which eventually grew into clusters of parallel platy crystals. The formation of a nanometer-thick well-ordered lepidocrocite film on a pristine calcite surface appears critical for the subsequent pseudomorphic overgrowth. Detachment of the lepidocrocite film from the dissolving calcite surface yielded a free-standing pseudomorphic iron oxyhydroxide shell, suggesting weak interactions between the shell and the calcite substrate. This growth mechanism yields the potential of using carbonate minerals as templates for pseudomorphic synthesis of iron oxyhydroxides having well-defined size and morphology.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ;  [2] ;  [3] ; ORCiD logo [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  3. Univ. of Delaware, Newark, DE (United States)
Publication Date:
Report Number(s):
BNL-203541-2018-JAAM; BNL-203608-2018-JAAM
Journal ID: ISSN 0897-4756; 140950; TRN: US1802722
Grant/Contract Number:
AC02-06CH11357; SC0012704
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 30; Journal Issue: 3; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (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; 25 ENERGY STORAGE; 36 MATERIALS SCIENCE
OSTI Identifier:
1427507
Alternate Identifier(s):
OSTI ID: 1433994; OSTI ID: 1436257

Yuan, Ke, Lee, Sang Soo, Wang, Jun, Sturchio, Neil C., and Fenter, Paul. Templating Growth of a Pseudomorphic Lepidocrocite Microshell at the Calcite–Water Interface. United States: N. p., Web. doi:10.1021/acs.chemmater.7b03921.
Yuan, Ke, Lee, Sang Soo, Wang, Jun, Sturchio, Neil C., & Fenter, Paul. Templating Growth of a Pseudomorphic Lepidocrocite Microshell at the Calcite–Water Interface. United States. doi:10.1021/acs.chemmater.7b03921.
Yuan, Ke, Lee, Sang Soo, Wang, Jun, Sturchio, Neil C., and Fenter, Paul. 2018. "Templating Growth of a Pseudomorphic Lepidocrocite Microshell at the Calcite–Water Interface". United States. doi:10.1021/acs.chemmater.7b03921.
@article{osti_1427507,
title = {Templating Growth of a Pseudomorphic Lepidocrocite Microshell at the Calcite–Water Interface},
author = {Yuan, Ke and Lee, Sang Soo and Wang, Jun and Sturchio, Neil C. and Fenter, Paul},
abstractNote = {The growth of lepidocrocite (gamma-FeOOH) has been observed through oxidation of Fe(II) on calcite (CaCO3). Here, we seek to understand the structural relation between lepidocrocite and the calcite substrate and its growth mechanism. The formation of iron oxyhydroxide layers having distinct morphologies was observed during the dissolution of calcite in acidic Fe(II)-rich solutions. A pseudomorphic lepidocrocite shell together with multiple iron oxyhydroxide layers encapsulated within the shell was imaged by optical and transmission X-ray microscopies. The presence of a several-nanometer-thick ordered lepidocrocite film was observed by X-ray reflectivity, with the lepidocrocite (100) plane oriented parallel to the calcite (104) surface. Lath-shaped lepidocrocite aggregates formed during the initial precipitation, which eventually grew into clusters of parallel platy crystals. The formation of a nanometer-thick well-ordered lepidocrocite film on a pristine calcite surface appears critical for the subsequent pseudomorphic overgrowth. Detachment of the lepidocrocite film from the dissolving calcite surface yielded a free-standing pseudomorphic iron oxyhydroxide shell, suggesting weak interactions between the shell and the calcite substrate. This growth mechanism yields the potential of using carbonate minerals as templates for pseudomorphic synthesis of iron oxyhydroxides having well-defined size and morphology.},
doi = {10.1021/acs.chemmater.7b03921},
journal = {Chemistry of Materials},
number = 3,
volume = 30,
place = {United States},
year = {2018},
month = {1}
}