New Platinum Alloy Catalysts for Oxygen Electroreduction Based on Alkaline Earth Metals

Ulrik Grønbjerg Vej-Hansen, M. Escudero-Escribano, Amado Andres Velazquez-Palenzuela, Paolo Malacrida, Jan Rossmeisl, I. E. L. Stephens, Ib Chorkendorff, Jakob Schiøtz

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The energy efficiency of polymer electrolyte membrane fuel cells is mainly limited by overpotentials related to the oxygen reduction reaction (ORR). In this paper, we present new platinum alloys which are active for the ORR and based on alloying Pt with very abundant elements, such as Ca. Theoretical calculations suggested that Pt5Ca and Pt5Sr should be active for the ORR. Electrochemical measurements show that the activity of sputter-cleaned polycrystalline Pt5Ca and Pt5Sr electrodes is enhanced by a factor of 5–7 relative to polycrystalline Pt. Accelerated stability testing shows that after 10,000 electrochemical cycles, the alloys still retain over half their activity. The stability is thus not quite on par with the similar Pt-lanthanide alloys, possibly due to the somewhat lower heat of formation.
Original languageEnglish
JournalElectrocatalysis
Volume8
Issue number6
Pages (from-to)594-604
Number of pages11
ISSN1868-2529
DOIs
Publication statusPublished - 2017

Keywords

  • Oxygen reduction reaction
  • Platinum alloys
  • Alkaline earths

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