Application of Pd-based electrodes as hydrogen diffusion anodes in alkaline fuel cells

In this work, the anode current and power densities of alkaline fuel cells using different Pd-based hydrogen diffusion anodes have been measured at 25 and 50 degrees C. A 25 mu m thick Pd foil submitted to different treatments and a Pt-catalyzed carbon-PTFE electrode were employed as anode and cathode, respectively. The results have been discussed in the light of chronoamperometry, scanning electron microscopy, and energy dispersive spectroscopy and Raman and X-ray photoelectron spectroscopy microanalyses. There was a strong tendency of the Pd foil to crease during the fuel cell operation and thus, the current and power densities increased with rime. These fuel cell characteristics appeared to be dramatically limited in the cast: of the use of rigid joints which did not permit the Pd foil deformation. This limitation was explained by a Gorsky effect. The PdO film produced on the Pd foil by heating in a furnace was a good catalyst for the overall anodic process. However, the cell performance decreased with time because of the oxide removal. The highest cell parameters were obtained when Pt black was electrodeposited on Pd black. The marked effect of Pt was explained by its catalytic activity on the interfacial reactions taking place at the gas side of the Pd foil. (C) 2000 The Electrochemical Society. S0013-4651(99)04-010-0. All rights reserved.