Evolution of the PtNi Bimetallic Alloy Fuel Cell Catalyst under Simulated Operational Conditions

Ivan Khalakhan, Marco Bogar, Mykhailo Vorokhta, Peter Kus, Yurii Yakovlev, Milan Dopita, Daniel John Seale Sandbeck, Serhiy Cherevko, Iva Matolinova, Heinz Amenitsch*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Comprehensive understanding of the catalyst corrosion dynamics is a prerequisite for the development of an efficient cathode catalyst in proton-exchange membrane fuel cells. To reach this aim, the behavior of fuel cell catalysts must be investigated directly under reaction conditions. Herein, we applied a strategic combination of in situ/online techniques: in situ electrochemical atomic force microscopy, in situ grazing incidence small angle X-ray scattering, and electrochemical scanning flow cell with online detection by inductively coupled plasma mass spectrometry. This combination of techniques allows in-depth investigation of the potential-dependent surface restructuring of a PtNi model thin film catalyst during potentiodynamic cycling in an aqueous acidic electrolyte. The study reveals a clear correlation between the upper potential limit and structural behavior of the PtNi catalyst, namely, its dealloying and coarsening. The results show that at 0.6 and 1.0 V RHE upper potentials, the PtNi catalyst essentially preserves its structure during the entire cycling procedure. The crucial changes in the morphology of PtNi layers are found to occur at 1.3 and 1.5 V RHE cycling potentials. Strong dealloying at the early stage of cycling is substituted with strong coarsening of catalyst particles at the later stage. The coarsening at the later stage of cycling is assigned to the electrochemical Ostwald ripening process.

Original languageEnglish
Pages (from-to)17602-17610
Number of pages9
JournalACS Applied Materials & Interfaces
Volume12
Issue number15
DOIs
Publication statusPublished - 15 Apr 2020

Keywords

  • fuel cells
  • bimetallic catalyst
  • dealloying
  • degradation
  • in situ electrochemical atomic force microscopy (EC-AFM)
  • in situ grazing incidence small angle X-ray scattering (GISAXS)
  • Ostwald ripening

ASJC Scopus subject areas

  • Environmental Science(all)

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

Cite this