Mechanistic study of fast performance decay of Pt-Cu alloy based catalyst layers for polymer electrolyte fuel cells through electrochemical impedance spectroscopy

Maximilian Grandi*, Matija Gatalo, Ana Rebeka Kamšek, Gregor Kapun, Kurt Mayer, Francisco Ruiz-Zepeda, Martin Šala, Bernhard Marius, Marjan Bele, Nejc Hodnik, Merit Bodner, Miran Gaberšček, Viktor Hacker

*Korrespondierende/r Autor/-in für diese Arbeit

Publikation: Beitrag in einer FachzeitschriftArtikelBegutachtung

Abstract

In the past, platinum–copper catalysts have proven to be highly active for the oxygen reduction reaction (ORR), but transferring the high activities measured in thin-film rotating disk elec-trodes (TF-RDEs) to high-performing membrane electrode assemblies (MEAs) has proven diffi-cult due to stability issues during operation. High initial performance can be achieved. Howev-er, fast performance decay on a timescale of 24 h is induced by repeated voltage load steps with H2/air supplied. This performance decay is accelerated if high relative humidity (>60% RH) is set for a prolonged time and low voltages are applied during polarization. The reasons and possible solutions for this issue have been investigated by means of electrochemical impedance spec-troscopy and distribution of relaxation time analysis (EIS–DRT). The affected electrochemical sub-processes have been identified by comparing the PtCu electrocatalyst with commercial Pt/C benchmark materials in homemade catalyst-coated membranes (CCMs). The proton transport resistance (Rpt) increased by a factor of ~2 compared to the benchmark materials. These results provide important insight into the challenges encountered with the de-alloyed PtCu/KB elec-trocatalyst during cell break-in and operation. This provides a basis for improvements in the catalysts’ design and break-in procedures for the highly attractive PtCu/KB catalyst system.
Originalspracheenglisch
Aufsatznummer3544
FachzeitschriftMaterials
Jahrgang16
Ausgabenummer9
DOIs
PublikationsstatusVeröffentlicht - 5 Mai 2023

ASJC Scopus subject areas

  • Physik der kondensierten Materie
  • Werkstoffwissenschaften (insg.)

Fields of Expertise

  • Advanced Materials Science
  • Mobility & Production

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