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Title: Engineering Ru@Pt Core-Shell Catalysts for Enhanced Electrochemical Oxygen Reduction Mass Activity and Stability

Improving the performance of oxygen reduction reaction (ORR) electrocatalysts is essential for the commercial efficacy of many renewable energy technologies, including low temperature polymer electrolyte fuel cells (PEFCs). Herein, we report highly active and stable carbon-supported Ru@Pt core-shell nanoparticles (Ru@Pt/C) prepared by a wet chemical synthesis technique. Through rotating disc electrode testing, the Ru@Pt/C achieves an ORR Pt mass-based activity of 0.50 A mg Pt -1 at 0.9 V versus the reversible hydrogen electrode (RHE), which exceeds the activity of the state-of-the-art commercial Pt/C catalyst as well as the Department of Energy 2020 PEFC electrocatalyst activity targets for transportation applications. The impact of various synthetic parameters, including Pt to Ru ratios and catalyst pretreatments (i.e., annealing) are thoroughly explored. Pt-based mass activity of all prepared Ru@Pt/C catalysts was found to exceed 0.4 mg Pt -1 across the range of compositions investigated, with the maximum activity catalyst having a Ru:Pt ratio of 1:1. This optimized composition of Ru@Pt/C catalyst demonstrated remarkable stability after 30,000 accelerated durability cycles (0.6 to 1.0 V vs. RHE at 125 mV s -1), maintaining 85% of its initial mass activity. Scanning transmission electron microscopy energy dispersive spectroscopy (STEM-EDS) analysis at various stages of electrochemical testing demonstratedmore » that the Pt shell can provide sufficient protection against the dissolution of the otherwise unstable Ru core.« less
Authors:
 [1] ; ORCiD logo [2] ;  [2] ;  [2]
  1. Stanford Univ., CA (United States). Dept. of Chemical Engineering
  2. Stanford Univ., CA (United States). Dept. of Chemical Engineering; SLAC National Accelerator Lab., Menlo Park, CA (United States). SUNCAT Center for Interface Science and Catalysis
Publication Date:
Grant/Contract Number:
AC02-76SF00515; SC0008685; 1066515
Type:
Accepted Manuscript
Journal Name:
Nanomaterials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2079-4991
Publisher:
MDPI
Research Org:
Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); USDOD
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; core-shell nanoparticles; electrocatalysis; oxygen reduction reaction; fuel cells; electrochemical energy technologies; nanomaterials synthesis
OSTI Identifier:
1425397