Oxygen reduction reaction activities for various-monolayer-thick Pt shells on PtxNi100-x(111)

Masato Asano, Ryutaro Kawamura, Naoto Todoroki, Toshimasa Wadayama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We studied the oxygen reduction reaction (ORR) activities for two monolayer (ML)-thick Pt on PtxNi100-x(111) (Pt2ML/PtxNi100-x(111)) model core-shell catalysts fabricated by molecular beam epitaxy (MBE). Low-energy electron diffraction patterns for all Pt2ML/PtxNi100-x(111) showed six-fold surface symmetry with longrange ordering, indicating a (111) atomic arrangement of the topmost Pt shell layers. Furthermore, scanning tunneling microscopy images of the Pt2ML/Pt50Ni50(111) and Pt2ML/Pt25Ni75(111) surfaces exhibited Moiré-like height modulations, which are likely induced by large lattice mismatches between the topmost Pt(111) shell layers and the Pt-Ni(111) substrates. The ORR activity of Pt2ML/PtxNi100-x(111) increased with the Ni composition; the enhancement factors are 8-, 18-, and 25-fold vs. Pt(111) for Pt2ML/Pt75Ni25(111), Pt2ML/Pt50Ni50(111), and Pt2ML/Pt25Ni75(111), respectively. The results suggested that the Pt surface strains induced by lattice mismatches between the Pt shells and Pt-Ni substrates increased with the Ni composition, leading to a marked enhancement in ORR activity, particularly for Pt2ML/Pt25Ni75(111).

Original languageEnglish
Title of host publicationPolymer Electrolyte Fuel Cells 15, PEFC 15
EditorsH. A. Gasteiger, V. K. Ramani, J. M. Fenton, T. J. Schmidt, D. J. Jones, K. E. Ayers, K. A. Perry, T. F. Fuller, B. S. Pivovar, K. Shinohara, F. N. Buchi, R. A. Mantz, C. Coutanceau, P. Strasser, A. Z. Weber, K. Swider-Lyons, H. Uchida, M. Edmundson, S. Mitsushima, S. R. Narayanan
PublisherElectrochemical Society Inc.
Pages619-624
Number of pages6
Edition17
ISBN (Electronic)9781607685395
DOIs
Publication statusPublished - 2015 Jan 1
EventSymposium on Polymer Electrolyte Fuel Cells 15, PEFC 2015 - 228th ECS Meeting - Phoenix, United States
Duration: 2015 Oct 112015 Oct 15

Publication series

NameECS Transactions
Number17
Volume69
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Other

OtherSymposium on Polymer Electrolyte Fuel Cells 15, PEFC 2015 - 228th ECS Meeting
CountryUnited States
CityPhoenix
Period15/10/1115/10/15

ASJC Scopus subject areas

  • Engineering(all)

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