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Title: Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: II. Influence of Ink Formulation, Catalyst Layer Uniformity and Thickness

Platinum electrocatalysts supported on high surface area and Vulcan carbon blacks (Pt/HSC, Pt/V) were characterized in rotating disk electrode (RDE) setups for electrochemical area (ECA) and oxygen reduction reaction (ORR) area specific activity (SA) and mass specific activity (MA) at 0.9 V. Films fabricated using several ink formulations and film-drying techniques were characterized for a statistically significant number of independent samples. The highest quality Pt/HSC films exhibited MA 870 ± 91 mA/mgPt and SA 864 ± 56 μA/cm 2 Pt while Pt/V had MA 706 ± 42 mA/mgPt and SA 1120 ± 70 μA/cm 2 Pt when measured in 0.1 M HClO 4, 20 mV/s, 100 kPa O 2 and 23±2°C. An enhancement factor of 2.8 in themeasured SA was observable on eliminating Nafion ionomer and employing extremely thin, uniform films (~4.5 μg/cm 2 Pt) of Pt/HSC. The ECA for Pt/HSC (99 ± 7 m2/gPt) and Pt/V (65 ± 5 m 2/gPt) were statistically invariant and insensitive to film uniformity/thickness/fabrication technique; accordingly, enhancements in MA are wholly attributable to increases in SA. Impedance measurements coupled with scanning electron microscopy were used to de-convolute the losses within the catalyst layer and ascribed to the catalyst layer resistance, oxygen diffusion, and sulfonatemore » anion adsorption/blocking. The ramifications of these results for proton exchange membrane fuel cells have also been examined.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States); Toyota Central R&D Labs., Inc., Aichi (Japan)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5900-65578
Journal ID: ISSN 0013-4651
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 162; Journal Issue: 12; Related Information: Journal of the Electrochemical Society; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; activity; benchmark; ink formulation; ORR; platinum; protocol; TF-RDE
OSTI Identifier:
1233476