Re-examination of the Pt Particle Size Effect on the Oxygen Reduction Reaction for Ultrathin Uniform Pt/C Catalyst Layers without Influence from Nafion
The platinum 'particle size effect' on the oxygen reduction reaction (ORR) has been re-evaluated using commercial Pt/C catalysts (2-10 nm Pt particle) and polycrystalline Pt (poly-Pt) in 0.1 M HClO4 with a rotating disk electrode method. Nafion-free catalyst layers were employed to obtain specific activities (SA) that were not perturbed (suppressed) by sulfonate anion adsorption/blocking. By using ultrathin uniform catalyst layers, O2 diffusion limitation was minimized as confirmed from the high SAs of our supported catalysts that were comparable to unsupported sputtered Pt having controlled sizes. The specific activity (SA) steeply increased for the particle sizes in the range -2-10 nm (0.8-1.8 mA/cm2Pt at 0.9 V vs. RHE) and plateaued over -10 nm to 2.7 mA/cm2Pt for bulk poly-Pt. On the basis of the activity trend for the range of particle sizes studied, it appears that the effect of carbon support on activity is negligible. The experimental results and the concomitant profile of SA vs. particle size was found to be in an agreement to a truncated octahedral particle model that assumes active terrace sites.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Hydrogen Fuel Cell Technologies Office
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1301812
- Report Number(s):
- NREL/JA-5900-66975
- Journal Information:
- Electrochimica Acta, Vol. 213; ISSN 0013-4686
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
Similar Records
Monodisperse core/shell Ni/FePt nanoparticles and their con-version to Ni/Pt to catalyze oxygen reduction
Enhanced Oxygen Reduction Activity on Pt/C for Nafion-free, Thin, Uniform Films in Rotating Disk Electrode Studies