Surface and catalytic properties of iron-platinum/carbon electrocatalysts for cathodic oxygen reduction in PAFC

Journal Article · Fri Jan 01 04:00:00 UTC 1993 · Journal of the Electrochemical Society; (United States)

OSTI ID:6548408

Kim, Kyong Tae; Hwang, Jung Tae; Kim, Young Gul; Chung, Jong Shik ^[1]

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1. 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), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 140:1; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

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CATALYTIC EFFECTS
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