Monitoring the Morphological Changes of Skeleton-PtCo Electrocatalyst during PEMFC Start-Up/Shut-Down probed by inâ
situ WAXS and SAXS.
ChemSusChem
; 17(17): e202400303, 2024 Sep 09.
Article
in En
| MEDLINE
| ID: mdl-38507245
ABSTRACT
Advanced inâ
situ analyses are indispensable for comprehending the catalyst aging mechanisms of Pt-based PEM fuel cell cathode materials, particularly during accelerated stress tests (ASTs). In this study, a combination of inâ
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 inâ
situ monitoring of structural changes in each crystal phase in detail. Remarkably, the inâ
situ WAXS measurements uncover two primary catalyst aging processes, namely the cobalt depletion (regimeâ
I) followed by the crystallite growth via Ostwald ripening and/or particle coalescence (regimeâ
II). Additionally, inâ
situ SAXS data reveal a continuous size growth over the AST. The Pt-enriched shell thickening based on the Co depletion within the first 100â
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 inâ
situ WAXS and SAXS techniques.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
ChemSusChem
Journal subject:
QUIMICA
/
TOXICOLOGIA
Year:
2024
Document type:
Article
Affiliation country:
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