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This content will become publicly available on April 26, 2017

Title: Palladium-platinum core-shell electrocatalysts for oxygen reduction reaction prepared with the assistance of citric acid

Core–shell structure is a promising alternative to solid platinum (Pt) nanoparticles as electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). A simple method of preparing palladium (Pd)–platinum (Pt) core–shell catalysts (Pd@Pt/C) in a gram-batch was developed with the assistance of citric acid. The Pt shell deposition involves three different pathways: galvanic displacement reaction between Pd atoms and Pt cations, chemical reduction by citric acid, and reduction by negative charges on Pd surfaces. The uniform ultrathin (~0.4 nm) Pt shell was characterized by in situ X-ray diffraction (XRD) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images combined with electron energy loss spectroscopy (EELS). Compared with state-of-the-art Pt/C, the Pd@Pt/C core–shell catalyst showed 4 times higher Pt mass activity and much better durability upon potential cycling. As a result, both the mass activity and durability were comparable to that of Pd@Pt/C synthesized by a Cu-mediated-Pt-displacement method, which is more complicated and difficult for mass production.
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  1. The Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. National Supercomputing Center in Shenzhen, Guangdong (People's Republic of China)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 2155-5435; R&D Project: 16060; KC0403020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Catalysis
Additional Journal Information:
Journal Volume: 6; Journal Issue: 6; Journal ID: ISSN 2155-5435
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
29 ENERGY PLANNING, POLICY, AND ECONOMY electrocatalysis; fuel cells; underpotential deposition; synchrotron; durability; Center for Functional Nanomaterials