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Title: Investigation of Iron Oxide Morphology in a Cyclic Redox Water Splitting Process for Hydrogen Generation

Abstract

A solar fuels generation research program is focused on hydrogen production by means of reactive metal water splitting in a cyclic iron-based redox process. Iron-based oxides are explored as an intermediary reactive material to dissociate water molecules at significantly reduced thermal energies. With a goal of studying the resulting oxide chemistry and morphology, chemical assistance via CO is used to complete the redox cycle. In order to exploit the unique characteristics of highly reactive materials at the solar reactor scale, a monolithic laboratory scale reactor has been designed to explore the redox cycle at temperatures ranging from 675 to 875 K. Using high resolution scanning electron microscope (SEM) and electron dispersive X-ray spectroscopy (EDS), the oxide morphology and the oxide state are quantified, including spatial distributions. These images show the change of the oxide layers directly after oxidation and after reduction. The findings show a significant non-stoichiometric O/Fe gradient in the atomic ratio following oxidation, which is consistent with a previous kinetics model, and a relatively constant, non-stoichiometric O/Fe atomic ratio following reduction.

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211516
DOE Contract Number:  
DE-AR0000184]
Resource Type:
Journal Article
Journal Name:
Materials
Additional Journal Information:
Journal Volume: 5; Journal Issue: 10; Journal ID: ISSN 1996-1944
Country of Publication:
United States
Language:
English

Citation Formats

Bobek, MM, Stehle, RC, and Hahn, DW. Investigation of Iron Oxide Morphology in a Cyclic Redox Water Splitting Process for Hydrogen Generation. United States: N. p., 2012. Web. doi:10.3390/ma5102003.
Bobek, MM, Stehle, RC, & Hahn, DW. Investigation of Iron Oxide Morphology in a Cyclic Redox Water Splitting Process for Hydrogen Generation. United States. doi:10.3390/ma5102003.
Bobek, MM, Stehle, RC, and Hahn, DW. Tue . "Investigation of Iron Oxide Morphology in a Cyclic Redox Water Splitting Process for Hydrogen Generation". United States. doi:10.3390/ma5102003.
@article{osti_1211516,
title = {Investigation of Iron Oxide Morphology in a Cyclic Redox Water Splitting Process for Hydrogen Generation},
author = {Bobek, MM and Stehle, RC and Hahn, DW},
abstractNote = {A solar fuels generation research program is focused on hydrogen production by means of reactive metal water splitting in a cyclic iron-based redox process. Iron-based oxides are explored as an intermediary reactive material to dissociate water molecules at significantly reduced thermal energies. With a goal of studying the resulting oxide chemistry and morphology, chemical assistance via CO is used to complete the redox cycle. In order to exploit the unique characteristics of highly reactive materials at the solar reactor scale, a monolithic laboratory scale reactor has been designed to explore the redox cycle at temperatures ranging from 675 to 875 K. Using high resolution scanning electron microscope (SEM) and electron dispersive X-ray spectroscopy (EDS), the oxide morphology and the oxide state are quantified, including spatial distributions. These images show the change of the oxide layers directly after oxidation and after reduction. The findings show a significant non-stoichiometric O/Fe gradient in the atomic ratio following oxidation, which is consistent with a previous kinetics model, and a relatively constant, non-stoichiometric O/Fe atomic ratio following reduction.},
doi = {10.3390/ma5102003},
journal = {Materials},
issn = {1996-1944},
number = 10,
volume = 5,
place = {United States},
year = {2012},
month = {10}
}