Monitoring the Morphological Changes of Skeleton-PtCo Electrocatalyst during PEMFC Start-Up/Shut-Down probed by in situ WAXS and SAXS.

Janssen, Marek; Drnec, Jakub; Martens, Isaac; Quinson, Jonathan; Pittkowski, Rebecca; Park, Daesung; Weber, Philipp; Arenz, Matthias; Oezaslan, Mehtap (2024). Monitoring the Morphological Changes of Skeleton-PtCo Electrocatalyst during PEMFC Start-Up/Shut-Down probed by in situ WAXS and SAXS. ChemSusChem, 17(17), e202400303. Wiley 10.1002/cssc.202400303

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Advanced in situ analyses are indispensable for comprehending the catalyst aging mechanisms of Pt-based PEM fuel cell cathode materials, particularly during accelerated stress tests (AST). In this study, a combination of in situ small-angle and wide-angle X-ray scattering (SAXS & WAXS) techniques were employed to establish correlations between structural parameters (crystal phase, quantity, and size) of a highly active skeleton-PtCo (sk-PtCo) catalyst and their degradation cycles within the potential range of the start-up/shut-down (SUSD) conditions. Despite the complex case of the sk-PtCo catalyst comprising two distinct fcc alloy phases, our complementary techniques enabled in situ monitoring of structural changes in each crystal phase in detail. Remarkably, the in situ WAXS measurements uncovered two primary catalyst aging processes, namely the cobalt depletion (regime I) followed by the crystallite growth via Ostwald ripening and/or particle coalescence (regime II). Additionally, in situ SAXS data reveal a continuous size growth over the AST. The Pt-enriched shell thickening based on the Co depletion within the first 100 SUSD cycles and particle growth induced by additional potential cycles were also collaborated by ex situ STEM-EELS. Overall, our work shows a comprehensive aging model for the sk-PtCo catalyst probed by complementary in situ WAXS and SAXS technique.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Arenz, Matthias

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

1864-564X

Publisher:

Wiley

Language:

English

Submitter:

Pubmed Import

Date Deposited:

27 Mar 2024 14:27

Last Modified:

12 Sep 2024 00:12

Publisher DOI:

10.1002/cssc.202400303

PubMed ID:

38507245

Uncontrolled Keywords:

accelerated stress test (AST) oxygen reduction reaction (ORR) skeleton-PtCo nanoparticles (NPs) small-angle and wide-angle X-ray scattering (SAXS & WAXS) start-up/shut-down (SUSD)

BORIS DOI:

10.48350/194589

URI:

https://boris.unibe.ch/id/eprint/194589

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