Characterization of Anodic Fuel Cell Catalysts Utilizing Various Surface Sensitive Techniques

McGovern, Matthew S.

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Description

Title

Characterization of Anodic Fuel Cell Catalysts Utilizing Various Surface Sensitive Techniques

Author(s)

McGovern, Matthew S.

Issue Date

2004

Doctoral Committee Chair(s)

Wieckowski, Andrzej

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Inorganic

Language

eng

Abstract

The spontaneously deposited Pt/Pd catalyst was optimized. The optimum palladium coverage for unsupported platinum black was theta = 0.79, whereas for carbon-supported platinum black it was theta = 1.39. The catalyst was also inspected via EC-IRAS, which indicated the presence of palladium on the surface and smaller particle sizes. It also revealed a potential tool for determining the poison from formic acid oxidation on palladium nanoparticles. Further, the efficacy of methyl formate oxidation on the catalyst was examined. This fuel was determined to hold no advantages over formic acid for oxidation with the Pt/Pd catalyst. This study also revealed the inadequacy of methanol oxidation on the Pt/Pd catalyst. Radiolabeling with electrochemistry was used to examine the poison/potential and poison/environment relationships. Poison from methanol and formic acid was determined to be strongly adsorbed CO, which was replaceable by CO passed through the electrolyte. The potentiometric differences between methanol and formic acid oxidation were also studied on a platinum black substrate. Formic acid oxidation was determined to go through the direct CO2 pathway, with poison buildup from CO formation only observed in a dynamic experiment in the HUPD region, indicating a reverse water-gas shift. Finally, we attempted to identify the poison species from formic acid oxidation on palladium. The experiments revealed that palladium is not significantly poisoned by carbon-containing species during formic acid oxidation.

Graduation Semester

2004

Type of Resource

text

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http://hdl.handle.net/2142/84137

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