Surface and catalytic properties of iron-platinum/carbon electrocatalysts for cathodic oxygen reduction in PAFC
- Pohang Inst. of Science and Technology (Korea, Republic of)
A Fe-Pt bimetallic catalyst was prepared by impregnating iron nitrate solution into a carbon-supported platinum catalyst. The catalyst was heat-treated in flowing Ar (nontreated) at 450 C (denoted as PF450), 750 C (PF750), and 900 C (PF900), or this process was followed by an acid-treatment in 1M H[sub 2]SO[sub 4] solution to leach out surface-enriched iron (acid-treated). The surface and catalytic properties of these catalysts were studied using H[sub 2]-O[sub 2] titration, XRD and TEM measurements, and oxygen reduction tests in PAFC. With increased heat-treatment temperature, the Pt surface area measured by hydrogen chemisorption (SA) decreases rapidly owing to particle sintering, alloying effect, and enrichment of iron on the surface. The mass activity (mA/g Pt) of the alloyed catalyst is about the same as that of pure Pt catalyst due to the particle sintering in the alloyed catalyst. However, the specific activity (mA/m[sup 2] Pt, based on SA) of the alloyed catalyst is estimated at twice that of pure Pt catalyst. The acid-treatment leads to dissolution of surface-enriched iron and results in an increase of the Pt surface area due to surface roughening. Except for PF450, the specific activities of both nontreated and acid-treated catalysts are the same, indicating that SA is a good measure of active site for the reaction. After acid treatment of the partially alloyed PF750, a twofold increase in the Pt surface area was observed when compared with the nontreated Pt-Fe alloy catalyst.
- OSTI ID:
- 6548408
- Journal Information:
- Journal of the Electrochemical Society; (United States), Vol. 140:1; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID ELECTROLYTE FUEL CELLS
ELECTROCATALYSTS
CARBON
CATALYTIC EFFECTS
SURFACE PROPERTIES
IRON
PLATINUM
BIMETALS
CHEMICAL PREPARATION
CHEMISORPTION
HEAT TREATMENTS
HYDROGEN
LEACHING
OXYGEN
PHOSPHORIC ACID
REDUCTION
SURFACE AREA
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
CATALYSTS
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
DIRECT ENERGY CONVERTERS
DISSOLUTION
ELECTROCHEMICAL CELLS
ELECTRON MICROSCOPY
ELEMENTS
FUEL CELLS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
METALS
MICROSCOPY
NONMETALS
PLATINUM METALS
SCATTERING
SEPARATION PROCESSES
SORPTION
SYNTHESIS
TRANSITION ELEMENTS
300503* - Fuel Cells- Materials
Components
& Auxiliaries