Catalysis, Architecture and the Electrochemical Performance of Microfibrous Cathodes for Hydrogen Peroxide-Based Fuel Cells

摘要

A pulse potential method for the deposition of a palladium/iridium catalyst onto the carbon microfibers of an array has been devised. A combination of LabView software, a National Instruments data acquisition card and an EG&G PARC Potentiostat were used to achieve the flexibility in control of potential, dwell time, and number of pulses. A significantly different morphology results from pulse potential (PP) deposition than from the baseline cyclic potential sweep (CPS) method. A reduction in deposition time of greater than 50% is also achieved. X-ray diffraction data have been used to conclude that the PP deposit is an alloy with a 1:1 atomic ratio of palladium to iridium. Polarization curves show that no significant difference in performance of a Mg-H_2O_2 semi-fuel cell occurs with a cathode catalyzed by PP compared with one catalyzed by CPS. Stable cell voltage over a six hour period is demonstrated. Results suggest better access to the catalyst by the H_2O_2 catholyte at reduced carbon microfiber array density. Further investigations are being pursued.