Highly Stable and Active Pt-Cu Oxygen Reduction Electrocatalysts Based on Mesoporous Graphitic Carbon Supports

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Chemistry of Materials

OSTI ID:1044676

Dai, Sheng ^[1]; Gupta, Gaurav ^[2]; Kumar, Pavan ^[2]; Wiggins-camacho, Jaclyn ^[2]; Wang, Xiqing ^[1]; Swinnea, Steven ^[2]; More, Karren Leslie ^[1]; Stevenson, Keith J ^[1]; Johnston, Keith ^[2]

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1. ORNL
2. University of Texas, Austin

The activity of oxygen reduction catalysts for fuel cells often decreases markedly (30-70%) during potential cycling tests designed to accelerate catalyst degradation. Herein we achieved essentially no loss in electrochemical surface area and catalyst activity during potential cycling from 0.5 to 1.2 V for presynthesized Pt-Cu nanoparticles of controlled composition that were infused into highly graphitic disordered mesoporous carbons (DMC). The high stability is favored by the strong metal-support interactions and low tendency for carbon oxidation, which mitigates the mechanisms of degradation. Electrochemical dealloying transforms the composition from Pt{sub 20}Cu{sub 80} to Pt{sub 85}Cu{sub 15} with a strained Pt-rich shell, which exhibits an enhanced ORR activity of 0.46 A/mg{sub Pt}, >4 fold that of pure Pt catalysts. The high uniformity in particle size and composition both before and after dealloying, as a consequence of the presynthesis/infusion technique, is beneficial for elucidating the mechanism of catalyst activity and, ultimately, for designing more active catalysts.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1044676
• Journal Information: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 19 Vol. 21; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
CARBON
CATALYSTS
ELECTROCATALYSTS
FUEL CELLS
OXIDATION
OXYGEN
PARTICLE SIZE
STABILITY
SURFACE AREA