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Title: Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design

Abstract

Ce-rich mixed metal oxides comprise a recently discovered class of ­electrocatalysts for the oxygen evolution reaction (OER). In particular, at current densities below 10 mA cm -2, Ni 0.3Fe 0.07Co 0.2Ce 0.43O x exhibits ­superior activity compared to the corresponding transition metal oxides, despite the relative inactivity of ceria. To elucidate the enhanced activity and underlying catalytic mechanism, detailed structural characterization of this quinary oxide electrocatalyst is reported in this paper. Transmission electron microscopy imaging of cross-section films as-prepared and after electrochemical testing reveals a stable two-phase nanostructure composed of 3–5 nm diameter crystallites of fluorite CeO 2 intimately mixed with 3–5 nm crystallites of transition metal oxides alloyed in the rock salt NiO structure. Dosing experiments demonstrate that an electron flux greater than ≈1000 e Å -2 s -1 causes the inherently crystalline material to become amorphous. A very low dose rate of 130 e Å -2 s -1 is employed for atomic resolution imaging using inline holography techniques to reveal a nanostructure in which the transition metal oxide nanocrystals form atomically sharp boundaries with the ceria nanocrystals, and these results are corroborated with extensive synchrotron X-ray absorption spectroscopy measurements. Finally, ceria is a well-studied cocatalyst for other heterogeneousmore » and electrochemical reactions, and our discovery introduces biphasic cocatalysis as a design concept for improved OER electrocatalysts.« less

Authors:
 [1];  [2];  [3];  [4];  [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Joint Center for Artificial Photosynthesis
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis. Physical Biosciences Division
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis. The Molecular Foundry
Publication Date:
Research Org.:
California Inst. of Technology (CalTech), Pasadena, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Inst. of Health (NIH) (United States)
OSTI Identifier:
1471246
Grant/Contract Number:  
SC0004993; AC02-05CH11231; P41GM103393
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 5; Journal Issue: 10; Journal ID: ISSN 1614-6832
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; aberration corrected electron microscopy; electrocatalysts; nanostructures; oxygen evolution reaction; X-ray absorption spectroscopy

Citation Formats

Haber, Joel A., Anzenburg, Eitan, Yano, Junko, Kisielowski, Christian, and Gregoire, John M. Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design. United States: N. p., 2015. Web. doi:10.1002/aenm.201402307.
Haber, Joel A., Anzenburg, Eitan, Yano, Junko, Kisielowski, Christian, & Gregoire, John M. Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design. United States. doi:10.1002/aenm.201402307.
Haber, Joel A., Anzenburg, Eitan, Yano, Junko, Kisielowski, Christian, and Gregoire, John M. Fri . "Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design". United States. doi:10.1002/aenm.201402307. https://www.osti.gov/servlets/purl/1471246.
@article{osti_1471246,
title = {Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design},
author = {Haber, Joel A. and Anzenburg, Eitan and Yano, Junko and Kisielowski, Christian and Gregoire, John M.},
abstractNote = {Ce-rich mixed metal oxides comprise a recently discovered class of ­electrocatalysts for the oxygen evolution reaction (OER). In particular, at current densities below 10 mA cm-2, Ni0.3Fe0.07Co0.2Ce0.43Ox exhibits ­superior activity compared to the corresponding transition metal oxides, despite the relative inactivity of ceria. To elucidate the enhanced activity and underlying catalytic mechanism, detailed structural characterization of this quinary oxide electrocatalyst is reported in this paper. Transmission electron microscopy imaging of cross-section films as-prepared and after electrochemical testing reveals a stable two-phase nanostructure composed of 3–5 nm diameter crystallites of fluorite CeO2 intimately mixed with 3–5 nm crystallites of transition metal oxides alloyed in the rock salt NiO structure. Dosing experiments demonstrate that an electron flux greater than ≈1000 e Å-2 s-1 causes the inherently crystalline material to become amorphous. A very low dose rate of 130 e Å-2 s-1 is employed for atomic resolution imaging using inline holography techniques to reveal a nanostructure in which the transition metal oxide nanocrystals form atomically sharp boundaries with the ceria nanocrystals, and these results are corroborated with extensive synchrotron X-ray absorption spectroscopy measurements. Finally, ceria is a well-studied cocatalyst for other heterogeneous and electrochemical reactions, and our discovery introduces biphasic cocatalysis as a design concept for improved OER electrocatalysts.},
doi = {10.1002/aenm.201402307},
journal = {Advanced Energy Materials},
number = 10,
volume = 5,
place = {United States},
year = {Fri Feb 27 00:00:00 EST 2015},
month = {Fri Feb 27 00:00:00 EST 2015}
}

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Cited by: 21 works
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