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Title: Ag–Pt compositional intermetallics made from alloy nanoparticles

Intermetallics are compounds with long-range structural order that often lies in a state of thermodynamic minimum. They are usually considered as favorable structures for catalysis due to their high activity and robust stability. However, formation of intermetallic compounds is often regarded as element specific. For instance, Ag and Pt do not form alloy in bulk phase through the conventional metallurgy approach in almost the entire range of composition. Herein, we demonstrate a bottom-up approach to create a new Ag–Pt compositional intermetallic phase from nanoparticles. By thermally treating the corresponding alloy nanoparticles in inert atmosphere, we obtained an intermetallic material that has an exceptionally narrow Ag/Pt ratio around 52/48 to 53/47, and a structure of interchangeable closely packed Ag and Pt layers with 85% on tetrahedral and 15% on octahedral sites. This rather unique stacking results in wavy patterns of Ag and Pt planes revealed by scanning transmission electron microscope (STEM). Finally, this Ag–Pt compositional intermetallic phase is highly active for electrochemical oxidation of formic acid at low anodic potentials, 5 times higher than its alloy nanoparticles, and 29 times higher than the reference Pt/C at 0.4 V (vs RHE) in current density.
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [1]
  1. Univ. of Illinois, Urbana, IL (United States). Dept. of Chemical and Biomolecular Engineering
  2. Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
FG02-01ER45923; DEFG02-01ER45923
Type:
Published Article
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 16; Journal Issue: 10; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Research Org:
Univ. of Illinois at Urbana-Champaign, IL (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ag−Pt; electrocatalysis; intermetallic compound; nanoparticle processing
OSTI Identifier:
1323986
Alternate Identifier(s):
OSTI ID: 1329044