The water uptake of several perfluorosulfonic acid membranes from liquid water over the temperature range 25 to 130~ and from water vapor at 80~ was determined. For water uptake from liquid water, the water uptake depended on the immersion temperature, the ion exchange capacity of the membrane, and the pretreatment of the membrane. The effects of pretreatment were not significant at immersion temperatures higher than 100 to 110~ For water uptake from water vapor at 80~ the sorption isotherms were similar in shape to those reported by previous investigators for 18.5 to 30~ although the water uptake at 80~ was less than that reported for the lower temperatures. The water uptake from water vapor of some membranes that have been found to give relatively good performance when used in polymer electrolyte fuel cells was higher then that observed with, e.g., Nafion|

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Diffusion coefficients for Cu(II), Dcu , were determined at 25~ in 0.51M H2SO4 over the concentration range 0.4 mM 1.0M CuSO4. The reported values of Dcu represent average values for the physical properties over the diffusion layer, and for the diffusing Cu(II) species, which consist of Cu ++ ions and Cu++SO4 = ion pairs. Thus, Dcu represents an effective value that is suitable for substitution into the various mass-transfer equations derived by assuming constant properties. At low CuSO4 concentrations (0.4-6 raM) static mercury drop electrode (SMDE) polarography using a modified version of the ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.83.63.20 Downloaded on 2014-06-24 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.83.63.20 Downloaded on 2014-06-24 to IP ABSTRACTAt current densities large in magnitude and also large compared to the exchange current density, a conducting disk in an insulating plane has a very nonuniform current distribution across the surface. The current distribution near the center is governed predominantly by ohmic effects, but near the edge, electrode kinetics become important. This paper describes the treatment of the current and potential distributions on the electrode, especially near the edge of the electrode where

A study of the anodic impurity peak that appears in the cyclic voltammograms of platinum electrodes in highly purified, hot, concentrated phosphoric acid is reported. The results indicate that this anodic impurity peak corresponds to the anodic oxidation of phosphorous acid. This phosphorous acid impurity appears to be formed at cathodic potentials by the reaction of the phosphoric acid electrolyte with adsorbed hydrogen. The electrochemical formation and anodic oxidation of the phosphorous acid impurity are enhanced at the elevated temperatures found in phosphoric acid fuel cells.

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