Epitaxial growth of twinned Au-Pt core-shell star-shaped decahedra as highly durable electrocatalysts

Ting Bian, Hui Zhang, Yingying Jiang, Chuanhong Jin, Jianbo Wu, Hong Yang, Deren Yang

Research output: Contribution to journalArticlepeer-review

Abstract

Pt epitaxial layer on a nanoparticle with twinned structure and well-defined shape is highly desirable in order to achieve high performance in both catalytic activity and durability toward oxygen reduction reaction (ORR). However, it remains tremendously challenging to produce conformal, heterogeneous, twinned nanostructures due to the high internal strain and surface energy of Pt. In addition, these twinned nanostructures may be subject to degradation in highly corrosive ORR environments due to the high energy of twin boundary. Here we report the synthesis of Au-Pt core-shell star-shaped decahedra bounded mainly by {111} facets, in which Pt shells with controlled thickness epitaxially grew on Au cores with a 5-fold twinned structure. The incorporation of the amine group decreases the surface energy of Pt by strong adsorption and thus facilitates the epitaxial growth of Pt on Au core instead of the dendritic growth. In addition, Br- ion could largely stabilize the {111} facets of Pt, which prevent the formation of spherical nanoparticles. The Au-Pt core-shell decahedra with thicker Pt shell exhibited enhanced ORR properties in terms of activity and durability. Specifically, AuPt1.03 star-shaped decahedra achieved the highest mass activity (0.94 mA/μgPt) and area activity (1.09 mA/cm2Pt), which is ∼6.7 and 5 times, respectively, as high as those of the commercial Pt/C (ETEK). Significantly, such star-shaped decahedra were highly stable with ∼10% loss in area activity and ∼20% loss in mass activity after 30 000 CV cycles in O2 saturated acid solution.

Original languageEnglish (US)
Pages (from-to)7808-7815
Number of pages8
JournalNano letters
Volume15
Issue number12
DOIs
StatePublished - Dec 9 2015

Keywords

  • Bimetallic nanocrystals
  • electrocatalysis
  • epitaxial growth
  • star-shaped decahedra
  • ultrathin shell

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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