Defect Engineering in Composition and Valence Band Center of Y 2 (Y x Ru 1- x ) 2 O 7-δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction.

Autor:	Ghosh B; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States., Zhang C; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States., Frick S; Department of Electronic Structure of Materials, Institute of Materials Science, Technical University of Darmstadt, Otto-Berndt-Straße 3, Darmstadt, Germany, 64287., Cho EJ; Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, 1304 W. Green Street, Urbana, Illinois 61801, United States.; Materials Research Laboratory, University of Illinois Urbana-Champaign, 104 S. Goodwin Avenue, Urbana, Illinois 61801, United States., Woods T; Center of Research and Educational Support, X-ray Diffraction Laboratory, School of Chemical Sciences, University of Illinois Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States., Yang Y; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States., Perry NH; Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, 1304 W. Green Street, Urbana, Illinois 61801, United States.; Materials Research Laboratory, University of Illinois Urbana-Champaign, 104 S. Goodwin Avenue, Urbana, Illinois 61801, United States., Klein A; Department of Electronic Structure of Materials, Institute of Materials Science, Technical University of Darmstadt, Otto-Berndt-Straße 3, Darmstadt, Germany, 64287., Yang H; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States.; Materials Research Laboratory, University of Illinois Urbana-Champaign, 104 S. Goodwin Avenue, Urbana, Illinois 61801, United States.
Jazyk:	angličtina
Zdroj:	Journal of the American Chemical Society [J Am Chem Soc] 2024 Jul 10; Vol. 146 (27), pp. 18524-18534. Date of Electronic Publication: 2024 May 31.
DOI:	10.1021/jacs.4c04292
Abstrakt:	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 Y 2 (Y x Ru 1- x ) 2 O 7-δ pyrochlore to achieve high catalytic activity. We found that partially replacing the B-site Ru 4+ cation with A-site Y 3+ in pyrochlore-structured Y 2 Ru 2 O 7-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 Y 2 (Y x Ru 1- x ) 2 O 7-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.
Databáze:	MEDLINE
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