The adsorption of water vapor on a highly microporous coconut-shell-derived carbon and a mesoporous wood-derived carbon was studied. These carbons were chosen as they had markedly different porous structures. The adsorption and desorption characteristics of water vapor on the activated carbons were investigated over the relative pressure range p/p° = 0−0.9 for temperatures in the range 285−313 K in a static water vapor system. The adsorption isotherms were analyzed using the Dubinin−Serpinski equation, and this provided an assessment of the polarity of the carbons. The kinetics of water vapor adsorption and desorption were studied with different amounts of preadsorbed water for set changes in pressure relative to the saturated vapor pressure (p/p°). The adsorption kinetics for each relative pressure step were compared and used to calculate the activation energies for the vapor pressure increments. The kinetic results are discussed in relation to their relative position on the equilibrium isotherm and the adsorption mechanism of water vapor on activated carbons.

X-ray absorption spectroscopy was used to identify specific types of nitrogen and sulfur-based carbon functionality present in the carbon black supports of fuel cell anodes and cathodes. The effects of these functional groups on the electrocatalytic performance of small platinum particles, dispersed on the carbon, during methanol oxidation and oxygen reduction were assessed. Electrodes functionalized with nitrogen had enhanced catalytic activities toward oxygen reduction and methanol oxidation relative to untreated electrodes. Although electrodes with sulfur functionality had higher oxygen reduction activities than untreated carbons, the activity of these electrodes toward methanol oxidation was found to be lower than electrodes manufactured from untreated carbon. It was found that carbon supports functionalized with both nitrogen and sulfur initiated the formation of Pt particles smaller in size than those observed on untreated carbon supports. ABSTRACT X-ray absorption spectroscopy was used to identify specific types of nitrogen and sulfur-based carbon functionality present in the carbon black supports of fuel cell anodes and cathodes. The effects of these functional groups on the electrocatalytic performance of small platinum particles, dispersed on the carbon, during methanol oxidation and oxygen reduction were assessed. Electrodes functionalized with nitrogen had enhanced catalytic activities toward oxygen reduction and methanol oxidation relative to untreated electrodes. Although electrodes with sulfur functionality had higher oxygen reduction activities than untreated carbons, the activity of these electrodes toward methanol oxidation was found to be lower than electrodes manufactured from untreated carbon. It was found that carbon supports functionalized with both nitrogen and sulfur initiated the formation of Pt particles smaller in size than those observed on untreated carbon supports.

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On pages 2326 and 2327, the last sentence on page 2326 and the first sentence on page 2327 should beThe nitrogen functionality of the carbon support appears to play a role in determining the size of the dispersed Pt crystallites, and/or influencing the electronic nature of Pt. For example, pyridine functionalities may provide lone pairs of electrons at the nitrogen site in an sp 2 orbital in the plane of the ring.