Defect Engineering in Composition and Valence Band Center of Y2(YxRu1-x)2O7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction

Bidipta Ghosh, Cheng Zhang, Stefanie Frick, En Ju Cho, Toby Woods, Yujie Yang, Nicola H. Perry, Andreas Klein, Hong Yang

Research output: Contribution to journalArticlepeer-review

Abstract

Oxygen evolution reaction (OER) takes place in various types of electrochemical devices that are pivotal for the conversion and storage of renewable energy. This paper describes a strategy in the design of solid-state structures of OER electrocatalysts through controlling the cation substitution on the active metal site and consequently valence band center position of site-mixed Y2(YxRu1-x)2O7−δ pyrochlore to achieve high catalytic activity. We found that partially replacing the B-site Ru4+ cation with A-site Y3+ in pyrochlore-structured Y2Ru2O7−δ modifies the oxidation state of B-site Ru from 4+ to 5+, as observed by electron paramagnetic resonance (EPR) spectroscopy but does not continuously increase the oxygen vacancy concentration in these oxygen substoichiometric compositions, as quantified by thermogravimetric analysis (TGA) decomposition studies. We found the increased Ru oxidation state leads to a downshift in valence band center. X-ray photoelectron spectroscopy (XPS) analysis was performed to quantitatively determine the optimal band center to be ∼1.27 eV below the Fermi energy level based on the analysis of the valence band edge of these Ru-based Y2(YxRu1-x)2O7−δ OER electrocatalysts. This work highlights that defect engineering can be a practical, effective approach to the optimization of oxidation state and electronic band center for high OER catalytic performance in a quantitative manner.

Original languageEnglish (US)
Pages (from-to)18524-18534
Number of pages11
JournalJournal of the American Chemical Society
Volume146
Issue number27
DOIs
StatePublished - Jul 10 2024

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint

Dive into the research topics of 'Defect Engineering in Composition and Valence Band Center of Y2(YxRu1-x)2O7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction'. Together they form a unique fingerprint.

Cite this