Authors: Justin Roller Roberto Neagu Frank Orfino Radenka Maric
Publish Date: 2012/02/23
Volume: 47, Issue: 11, Pages: 4604-4611
Abstract
The present study examines the physical and electrochemical properties of platinum particles generated by a combustion method for use in oxygen reduction on the cathode side of a proton exchange fuel cell PEMFC This method employs a onestep openatmosphere and dry deposition technique called reactive spray deposition technology RSDT The objective of this study is to characterize the intrinsic activity of the platinum produced for incorporation into lowloading cathode electrodes in high performing membrane electrode assemblies MEA The process allows for independent realtime control of the carbon platinum and ionomer ratios in the final electrode In this research work we examine the oxygen reduction reaction via a rotating disk three electrode setup to understand the intrinsic activity of the assprayed platinum as well as platinum condensed onto a carbon support The mass and specific activities were measured in a 01 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma AESICP Microscopy results indicate that the platinum particle sizes are 5 nm σ = 28 nm in diameter while TEM and XRD show that the platinum generated by the process is pure and crystalline without bulk oxides or precursor material present The initial rotating disk electrode result shows that the RSDT technique is capable of producing catalysts with an oxygen reduction mass activity at 09 V of 200 mA/mgPt rotating at 1600 rpm and 30 °C The electrochemically active surface area approaches 120 m2/g for the platinum carbon and ionomer samples and the unsupported sample with only platinum has an active area of 92 m2/g The rather larger surface area of the unsupported sample exists when the platinum is deposited as a highly porous nanostructured layer that allows for high penetration of reactant
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