Title

Morphological Characteristics of PTFE Bonded Gas Diffusion Electrodes

Abstract

We have investigated the morphological and absorptive characteristics of the electrocatalyst layer of PTFE bonded gas diffusion electrodes. The electrocatalyst layer microstructure was varied by using different preparative conditions (320-360°C sintering temperature and 20-60% PTFE content). We measured the pore size distribution and the electrolyte uptake for each electrode. From these data we calculated porosities and electrolyte volume fractions of the electrocatalyst layer and agglomerate regions The electrocatalyst layer porosity and electrolyte volume fraction depend directly on the preparative conditions, while the agglomerate porosity and the macropore porosity are not influenced significantly. We proposed and evaluated a theoretical expression for the Pt utilization in the electrocatalyst layer using our measured porosities and electrolyte volume fractions. These results agree well with electrochemical measurements of active Pt surface area using cyclic voltammetry. The percentage acid occupation (PAO) was also found to be a good property for correlating morphological-absorptive characteristics and Pt utilization.

Department(s)

Physics

Keywords and Phrases

Catalysts--Morphology; Catalysts--Porosity; Electrodes--Microstructure; Gases--Diffusion; Polytetrafluoroethylenes, Cyclic Voltammetry; Electrocatalyst; Gas Diffusion Electrodes; Macroporosity; Percentage Acid Occupation; Pore Size Distribution, Electrodes, Electrochemical

International Standard Serial Number (ISSN)

0013-4686

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1991 Elsevier, All rights reserved.

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