Performance of Silicotungstic Acid Modified Platinum Cathodes at High Temperature and Low Relative Humidity for PEMFCs

Abstract

Silicotungstic acid was added to Pt/C electrodes of proton exchange membrane fuel cells using four fabrication processes to evaluate the catalytic effect on oxygen reduction. The electrochemical surface area of the catalyst was shown to decrease with increasing concentration of silicotungstic acid when directly added to the ink mixture, however indirect addition and pH neutralization methods showed a surface area increase. Performance of 25 cm 2 cells was evaluated by obtaining polarization curves at three conditions 80 • C/35% relative humidity, 80 • C/100% relative humidity and 120 • /35% relative humidity with H 2 /air and H 2 /O 2 . Activity of the electrodes with silicotungstic acid with Pt/C was found to increase by as much as 17.7 mA/cm 2 at an overpotential of 0.3 V compared to electrodes with Pt/C at the 120 • C/35% relative humidity condition. Limiting current of cells treated with silicotungstic acid were increased by as much as 600 mA/cm 2 at the 120 • C/35% relative humidity condition. The improvement in performance is attributed to improved proton mobility in the electrode.

Performance of H2-fed fuel cell with chitosan/silicotungstic acid membrane as proton conductor

“…In fact, according to the literature, hybrid polymer-silicotungstic acid (STA) membranes have a high thermal stability, promising mechanical strength and proton conductivity [10,[15][16][17][18]. Moreover, the addition of STA to the electrodes of polymer electrolyte membranes fuel cells is reported to enhance the activity of platinum towards oxygen reduction reaction and the stability of the membrane [19][20][21].…”

Proton‐conductive membranes based on vanadium substituted heteropoly acids with Keggin structure and polymers

“…With growing concerns on the depletion of petroleum‐based energy resources and climate change, renewable energy systems have been considered as a key technology for solving global environment and energy problems by reducing emission from fossil fuels. Polymer electrolyte membrane fuel cells (PEMFCs), a source of electrical power for transportation, residential and portable applications, were extensively researched in recent years due to their high efficiency, clean production and low‐temperature operation . Polymer electrolyte membrane (PEM) is recognized as the key element among the primary components to improve fuel cell durability, performance as well as cost‐effective to ensure sustainable commercialization of polymer electrolyte fuel cells .…”