Loading…

Corrosion Resistance and Catalytic Activity toward the Oxygen Reduction Reaction of CoCrFe x Ni (0 ≤ x ≤ 0.7) Thin Films

Corrosion resistance and catalytic activity toward the oxygen reduction reaction (ORR) in an alkaline environment are two key properties for water recombination applications. In this work, CoCrFe x Ni (0 ≤ x ≤ 0.7) thin films were deposited by magnetron sputtering on polished steel substrates. The n...

Full description

Saved in:
Bibliographic Details
Published in:ACS applied energy materials 2022-09, Vol.5 (9), p.10838-10848
Main Authors: Linder, Clara, Rao, Smita G., Boyd, Robert D., le Febvrier, Arnaud, Eklund, Per, Munktell, Sara, Björk, Emma M.
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Corrosion resistance and catalytic activity toward the oxygen reduction reaction (ORR) in an alkaline environment are two key properties for water recombination applications. In this work, CoCrFe x Ni (0 ≤ x ≤ 0.7) thin films were deposited by magnetron sputtering on polished steel substrates. The native passive layer was 2–4 nm thick and coherent to the columnar grains determined by transmission electron microscopy. The effect of Fe on the corrosion properties in 0.1 M NaCl and 1 M KOH and the catalytic activity of the films toward ORR were investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements indicate that CoCrFe0.7Ni and CoCrFe0.3Ni have the highest corrosion resistance of the studied films in NaCl and KOH, respectively. The high corrosion resistance of the CoCrFe0.7Ni film in NaCl was attributed to the smaller overall grain size, which leads to a more homogeneous film with a stronger passive layer. For CoCrFe0.3Ni in KOH, it was attributed to a lower Fe dissolution into the electrolyte and the build-up of a thick and protective hydroxide layer. Scanning Kelvin probe force microscopy showed no potential differences globally in any of the films, but locally, a potential gradient between the top of the columns and grain boundaries was observed. Corrosion of the films was likely initiated at the top of the columns where the potential was lowest. It was concluded that Fe is essential for the electrochemical activation of the surfaces and the catalytic activity toward ORR in an alkaline medium. The highest catalytic activity was recorded for high Fe-content films (x ≥ 0.5) and was attributed to the formation of platelet-like oxide particles on the film surface upon anodization. The study showed that the combination of corrosion resistance and catalytic activity toward ORR is possible for CoCrFe x Ni, making this material system a suitable candidate for water recombination in an alkaline environment.
ISSN:2574-0962
2574-0962
DOI:10.1021/acsaem.2c01499