A High-Entropy Oxide as High-Activity Electrocatalyst for Water Oxidation

Mohana V. Kante, Moritz L. Weber, Shu Ni, Iris C.G. van den Bosch, Emma van der Minne, Lisa Heymann, Lorenz J. Falling, Nicolas Gauquelin, Martina Tsvetanova, Daniel M. Cunha, Gertjan Koster, Felix Gunkel, Slavomír Nemšák, Horst Hahn, Leonardo Velasco Estrada*, Christoph Baeumer*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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High-entropy materials are an emerging pathway in the development of high-activity (electro)catalysts because of the inherent tunability and coexistence of multiple potential active sites, which may lead to earth-abundant catalyst materials for energy-efficient electrochemical energy storage. In this report, we identify how the multication composition in high-entropy perovskite oxides (HEO) contributes to high catalytic activity for the oxygen evolution reaction (OER), i.e., the key kinetically limiting half-reaction in several electrochemical energy conversion technologies, including green hydrogen generation. We compare the activity of the (001) facet of LaCr0.2Mn0.2Fe0.2Co0.2Ni0.2O3-δ with the parent compounds (single B-site in the ABO3 perovskite). While the single B-site perovskites roughly follow the expected volcano-type activity trends, the HEO clearly outperforms all of its parent compounds with 17 to 680 times higher currents at a fixed overpotential. As all samples were grown as an epitaxial layer, our results indicate an intrinsic composition-function relationship, avoiding the effects of complex geometries or unknown surface composition. In-depth X-ray photoemission studies reveal a synergistic effect of simultaneous oxidation and reduction of different transition metal cations during the adsorption of reaction intermediates. The surprisingly high OER activity demonstrates that HEOs are a highly attractive, earth-abundant material class for high-activity OER electrocatalysts, possibly allowing the activity to be fine-tuned beyond the scaling limits of mono- or bimetallic oxides.

Original languageEnglish
Pages (from-to)5329-5339
Number of pages11
JournalACS nano
Issue number6
Publication statusPublished - 28 Mar 2023


  • Green hydrogen
  • High-entropy oxides
  • Oxygen evolution reaction (OER)
  • Perovskite oxide catalysts
  • Scaling reactions
  • Water electrolysis
  • UT-Hybrid-D

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