skip to main content

DOE PAGESDOE PAGES

Title: Synthesis and Characterization of Pt–Ag Alloy Nanocages with Enhanced Activity and Durability toward Oxygen Reduction

Engineering the elemental composition of metal nanocrystals offers an effective strategy for the development of catalysts or electrocatalysts with greatly enhanced activity. Herein, we report the synthesis of Pt–Ag alloy nanocages with an outer edge length of 18 nm and a wall thickness of about 3 nm. Such nanocages with a composition of Pt 19Ag 81 could be readily prepared in one step through the galvanic replacement reaction between Ag nanocubes and a Pt(II) precursor. Here, after 10 000 cycles of potential cycling in the range of 0.60–1.0 V as in an accelerated durability test, the composition of the nanocages changed to Pt 56Ag 44, together with a specific activity of 1.23 mA cm –2 toward oxygen reduction, which was 3.3 times that of a state-of-the-art commercial Pt/C catalyst (0.37 mA cm –2) prior to durability testing. Density functional theory calculations attributed the increased activity to the stabilization of the transition state for breaking the O–O bond in molecular oxygen. Even after 30 000 cycles of potential cycling, the mass activity of the nanocages only dropped from 0.64 to 0.33 A mg –1 Pt, which was still about two times that of the pristine Pt/C catalyst (0.19 A mg –1more » Pt).« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [4] ;  [1] ;  [2] ;  [1]
  1. Georgia Institute of Technology and Emory Univ., Atlanta, GA (United States)
  2. Univ. of Wisconsin-Madison, Madison, WI (United States)
  3. Georgia Inst. of Technology, Atlanta, GA (United States)
  4. Georgia Inst. of Technology, Atlanta, GA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
FG02-05ER15731
Type:
Accepted Manuscript
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 Wisconsin-Madison, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
Environmental Molecular Sciences Laboratory; the Center for Nanoscale Materials at Argonne National Laboratory; the National Energy Research Scientific Computing Center (NERSC); and the UW-Madison Center for High Throughput Computing (CHTC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; density functional theory; nanocage; oxygen reduction reaction; platinum-based catalyst; Pt−Ag alloy
OSTI Identifier:
1398266