Atomic-Level Observation of Potential-Dependent Variations at the Surface of an Oxide Catalyst during Oxygen Evolution Reaction.

Autor: Park CH; Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Lee H; Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Choi JS; KAIST Analysis Center, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Yun TG; Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Lim Y; Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Bae HB; KAIST Analysis Center, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea., Chung SY; Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
Jazyk: angličtina
Zdroj: Advanced materials (Deerfield Beach, Fla.) [Adv Mater] 2024 Sep; Vol. 36 (38), pp. e2403392. Date of Electronic Publication: 2024 Jul 16.
DOI: 10.1002/adma.202403392
Abstrakt: Understanding the intricate details of the surface atomic structure and composition of catalysts during the oxygen evolution reaction (OER) is crucial for developing catalysts with high stability in water electrolyzers. While many notable studies highlight surface amorphization and reconstruction, systematic analytical tracing of the catalyst surface as a function of overpotential remains elusive. Heteroepitaxial (001) films of chemically stable and lattice-oxygen-inactive LaCoO 3 are thus utilized as a model catalyst to demonstrate a series of atomic-resolution observations of the film surface at different anodic potentials. The first key finding is that atoms at the surface are fairly dynamic even at lower overpotentials. Angstrom-scale atomic displacements within the perovskite framework are identified below a certain potential level. Another noteworthy feature is that amorphization (or paracrystallization) with no long-range order is finally induced at higher overpotentials. In particular, surface analyses consistently support that the oxidation of lattice oxygen is coupled with amorphous phase formation at the high potentials. Theoretical calculations also reveal an upward shift of oxygen 2p states toward the Fermi level, indicating enhanced lattice oxygen activation when atom displacement occurs more extensively. This study emphasizes that the degradation behavior of OER catalysts can distinctively vary depending on the overpotential level.
(© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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