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Journal of the Electrochemical Society, Vol.161, No.12, F1307-F1313, 2014
Performance of Silicotungstic Acid Modified Platinum Cathodes at High Temperature and Low Relative Humidity for PEMFCs
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 degrees C/35% relative humidity, 80 degrees C/100% relative humidity and 120 degrees/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 degrees 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 degrees C/35% relative humidity condition. The improvement in performance is attributed to improved proton mobility in the electrode. (C) The Author(s) 2014. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected]. All rights reserved.