Achieving high oxygen evolution reaction (OER) activity while maintaining performance stability is a key challenge for designing perovskite structure oxide OER catalysts, which are often unstable in alkaline environments transforming into an amorphous phase. While the chemical and structural transformation occurring during electrolysis at the electrolyte–catalyst interface is now regarded as a crucial factor influencing OER activity, here, using La0.7Sr0.3CoO3−
Electrocatalytic reactions are known to take place at the catalyst/electrolyte interface. Whereas recent studies of size‐dependent activity in nanoparticles and thickness‐dependent activity of thin films imply that the sub‐surface layers of a catalyst can contribute to the catalytic activity as well, most of these studies consider actual modification of the surfaces. In this study, the role of catalytically active sub‐surface layers was investigated by employing atomic‐scale thickness control of the La0.7Sr0.3MnO3(LSMO) films and heterostructures, without altering the catalyst/electrolyte interface. The activity toward the oxygen evolution reaction (OER) shows a non‐monotonic thickness dependence in the LSMO films and a continuous screening effect in LSMO/SrRuO3heterostructures. The observation leads to the definition of an “electrochemically‐relevant depth” on the order of 10 unit cells. This study on the electrocatalytic activity of epitaxial heterostructures provides new insight in designing efficient electrocatalytic nanomaterials and core‐shell architectures.
more » « less- PAR ID:
- 10448021
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small
- Volume:
- 17
- Issue:
- 49
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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