In situ electrochemical grazing incidence small angle X-ray scattering: From the design of an electrochemical cell to an exemplary study of fuel cell catalyst degradation

Marco Bogar, Ivan Khalakhan, Alessandro Gambitta, Yurii Yakovlev, Heinz Amenitsch*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Nowadays, electrochemistry has a considerable technological impact, involving fuel cells, super capacitors and batteries. These devices are based on complex architectures, which complicates monitoring their evolution in situ under operating conditions to reveal the reasons for reduced lifetime and performances. Here, we present a design of a multipurpose electrochemical cell for grazing incidence small and wide angle X-ray scattering (GISAXS and GIWAXS) where the environment for operating conditions can be recreated. We focus on proton exchange membrane fuel cells (PEMFCs) which operational conditions are simulated by means of potentiodynamic-based accelerated stress tests, applied to a thin film of Pt nanoparticles representing a model system of a benchmark catalyst. Two different upper potentials are used to mimic fuel cell operating conditions: at 1.0 V RHE the catalyst film preserves its initial morphology, while at 1.5 V RHE (simulating fuel cell start-up/shut-down cycles) significant coarsening has been observed. The initial dimension of the Pt particles of 4.0 nm increases to 8.7 nm due to the predominant process of coalescence and final Ostwald ripening. In parallel, the distance between the particles increases, the catalyst film (9 nm thick) becomes thinner at first and exhibit a higher roughness at the end.

Original languageEnglish
Article number229030
JournalJournal of Power Sources
Volume477
DOIs
Publication statusPublished - 30 Nov 2020

Keywords

  • Fuel cells
  • Electrochemistry
  • Grazing incidence small angle X-ray scattering
  • Ostwald ripening
  • Nanoparticles
  • Catalyst layer

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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