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Insights into the durability of Co-Fe spinel oxygen evolution electrocatalysts: via operando studies of the catalyst structure

Insights into the durability of Co-Fe spinel oxygen evolution electrocatalysts: via operando studies of the catalyst structure
Insights into the durability of Co-Fe spinel oxygen evolution electrocatalysts: via operando studies of the catalyst structure

Elemental reorganisation and oxidation state changes of key active sites in Co-Fe spinels are investigated by in situ X-ray photoemission spectroscopy (XPS) and operando X-ray absorption spectroscopy (XAS) under oxygen evolution operating conditions. The combination of the two techniques allows identifying both the surface and bulk modifications on the oxides and relating them to the activity loss during extended cycling. The results show that Co-Fe spinels experience a surface irreversible phase evolution under oxygen evolution reaction (OER) conditions, resulting in the formation of an amorphous layer composed of new stable Co(iii) and Fe(iii) species. Accelerated ageing tests show that the durability, intended as the performance loss during cycling treatments, is not directly related to the structural/chemical stability of the spinels but to the new species formed at the surface due to the electrochemical work. Thus, the material that experienced more significant changes was also the most durable one, demonstrating that the understanding of the chemical and/or structural evolution of the materials during the catalytic process can be the key for the design of highly active and stable catalysts.

2050-7488
7034-7041
Calvillo, L.
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Carraro, F.
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Vozniuk, O.
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Celorrio, V.
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Nodari, L.
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Russell, A.E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Debellis, D.
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Fermin, D.
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Cavani, F.
a4949981-10a9-42ab-9842-95d6f732c482
Agnoli, S.
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Granozzi, G.
e1561b71-a42d-4c72-9028-3fb07183fceb
Calvillo, L.
05ff21ed-97ce-4ea4-9b73-f4c181be59b0
Carraro, F.
ef93d02a-ccb7-4d8c-aca8-fb4106cc5e4a
Vozniuk, O.
9f7aee7c-ee37-4737-90fc-d52e9c0d3a60
Celorrio, V.
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Nodari, L.
8599b80f-4a46-4f93-bf3c-38ba33470237
Russell, A.E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Debellis, D.
11cb20c2-f063-4b68-92a8-80a451b315ca
Fermin, D.
5bec088e-9bd0-43ed-b1fb-1615673e8b57
Cavani, F.
a4949981-10a9-42ab-9842-95d6f732c482
Agnoli, S.
aed87283-7fc7-489a-9c88-766e21c1f835
Granozzi, G.
e1561b71-a42d-4c72-9028-3fb07183fceb

Calvillo, L., Carraro, F., Vozniuk, O., Celorrio, V., Nodari, L., Russell, A.E., Debellis, D., Fermin, D., Cavani, F., Agnoli, S. and Granozzi, G. (2018) Insights into the durability of Co-Fe spinel oxygen evolution electrocatalysts: via operando studies of the catalyst structure. Journal of Materials Chemistry A, 6 (16), 7034-7041. (doi:10.1039/c7ta10892c).

Record type: Article

Abstract

Elemental reorganisation and oxidation state changes of key active sites in Co-Fe spinels are investigated by in situ X-ray photoemission spectroscopy (XPS) and operando X-ray absorption spectroscopy (XAS) under oxygen evolution operating conditions. The combination of the two techniques allows identifying both the surface and bulk modifications on the oxides and relating them to the activity loss during extended cycling. The results show that Co-Fe spinels experience a surface irreversible phase evolution under oxygen evolution reaction (OER) conditions, resulting in the formation of an amorphous layer composed of new stable Co(iii) and Fe(iii) species. Accelerated ageing tests show that the durability, intended as the performance loss during cycling treatments, is not directly related to the structural/chemical stability of the spinels but to the new species formed at the surface due to the electrochemical work. Thus, the material that experienced more significant changes was also the most durable one, demonstrating that the understanding of the chemical and/or structural evolution of the materials during the catalytic process can be the key for the design of highly active and stable catalysts.

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Accepted/In Press date: 20 March 2018
e-pub ahead of print date: 21 March 2018

Identifiers

Local EPrints ID: 421951
URI: https://eprints.soton.ac.uk/id/eprint/421951
ISSN: 2050-7488
PURE UUID: 16415cb6-f2eb-4136-ae9c-a22d26180f99
ORCID for A.E. Russell: ORCID iD orcid.org/0000-0002-8382-6443

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Date deposited: 11 Jul 2018 16:30
Last modified: 22 Mar 2019 05:01

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