Ag–Pt Compositional Intermetallics Made from Alloy Nanoparticles

Journal Article · Mon Sep 12 00:00:00 EDT 2016 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.6b03302· OSTI ID:1323986

Pan, Yung-Tin ^[1]; Yan, Yuqi ^[1]; Shao, Yu-Tsun ^[2]; Zuo, Jian-Min ^[2]; Yang, Hong ^[1]

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1. University of Illinois at Urbana—Champaign, Department of Chemical and Biomolecular Engineering, 114 Roger Adam Laboratory, MC-712, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
2. University of Illinois at Urbana—Champaign, Department of Materials Science and Engineering, 1006 Materials Research Laboratory, 104 South Goodwin Avenue, Urbana, Illinois 61801, United States

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.

• Research Organization: Univ. of Illinois at Urbana-Champaign, IL (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: DEFG02-01ER45923; FG02-01ER45923
• OSTI ID: 1323986
• Alternate ID(s): OSTI ID: 1329044
• Journal Information: Nano Letters, Journal Name: Nano Letters Vol. 16 Journal Issue: 10; ISSN 1530-6984
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Ag−Pt
electrocatalysis
intermetallic compound
nanoparticle processing