Enhanced electrocatalytic activity of cobalt-free oxygen electrodes via surface modifications
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Accepted version
Author(s)
Type
Journal Article
Abstract
Improving performance of cobalt-free oxygen electrodes for intermediate temperature operation (600-700 °C) is a major challenge in realizing a cost-effective solid oxide technology. A recent model system study suggests that modifying surface acidity can enhance oxygen exchange rates. Inspired by these findings, this study investigates the impact of surface acidity on a technologically relevant electrode architecture. Infiltrating (La0.6Sr0.4)0.98FeO3-δ/Ce0.9Gd0.1O2-δ (LSF/CGO) electrodes with nitrate precursors, to form secondary surface phases of different acidity, can result in a two-fold polarization resistance (Rp) reduction. Basic oxides generally improve performance, while acidic ones hamper it, however, Rp does not scale directly with Smith acidity. It is found that Rp scales equally well with precursor solution pH and can be reduced threefold (1.07 → 0.36 Ω cm2) under alkaline conditions. This demonstrates that the chemical environment during infiltration impacts electrode properties and raises the question of whether precursor pH or secondary phases formed during nitrate decomposition dominate the improved performance most. Surface-sensitive techniques and electronic-structure calculations probe the effect of high precursor pH. While several mechanisms may contribute, the benefits of a high pH treatment are likely related to preferential Sr leaching and redeposition during heat treatment, which modifies surface acidity and exposes subsurface layers.
Date Acceptance
2026-10-12
Citation
Advanced Functional Materials
ISSN
1616-301X
Publisher
Wiley
Journal / Book Title
Advanced Functional Materials
Copyright Statement
Copyright This paper is embargoed until publication. Once published the author’s accepted manuscript will be made available under a CC-BY License in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy).
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Publication Status
Accepted