Development of analytical techniques to study H2s poisoning of PEMFCs and components

Conference · Tue Jan 01 04:00:00 EST 2008

DOI:https://doi.org/10.1149/1.3142766· OSTI ID:956627

Brosha, Eric L ^[1]; Rockward, Tommy ^[1]; Uribe, Francisco A ^[1]; Garzon, Fernando H ^[1]

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1. Los Alamos National Laboratory

Polymer electrolyte membrane fuel cells are sensitive to impurities that may be present in either the oxidizer or fuel. H{sub 2}S, even at the ppb level, will have a dramatic and adverse affect on fuel cell performance. Not only is it important to know a particular material's affinity to adsorb H{sub 2}S, when considering materials for PEMFC applications, issues such as permeation and crossover rates also become extremely important Several experimental methods have been developed to quantify H{sub 2}S adsorption onto surfaces and to quantify H{sub 2}S permeation through Nafion(reg.) membranes using readily available and inexpensive Ag/AgS ion probes. In addition to calculating the H{sub 2}S uptake on commonly used XC-72 carbon supports and PtlXC-72 catalysts, the H{sub 2}S permeability through dry and humidified Nafion(reg.) PEMFC membranes was also studied using these specialized techniques. In each ion probe experiment performed, a sulfide anti-oxidant buffer solution was used to trap and concentrate trace quantities of H{sub 2}S during the course of the measurement. Crossover experiments were conducted for up to 24 hours in order to achieve sulfide ion concentrations high enough to be precisely determined by subsequent titration with Pb(NO{sub 3}){sub 2}. By using these techniques, we have confirmed H{sub 2}S crossover in Nafion(reg.) membranes and have calculated preliminary rates of H{sub 2}S crossover.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 956627
• Report Number(s): LA-UR-08-07840; LA-UR-08-7840
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADSORPTION
AFFINITY
CARBON
CATALYSTS
CHEMICAL ANALYSIS
ELECTROLYTES
FUEL CELLS
HYDROGEN SULFIDES
IMPURITIES
ION MEMBRANES
OXIDIZERS
PERFORMANCE
PERMEABILITY
POISONING
POLYMERS
PROTON EXCHANGE MEMBRANE FUEL CELLS
SULFIDES
SURFACES
TITRATION
TRAPS
UPTAKE