β Scribed by Chee Kok Poh; San Hua Lim; Hui Pan; Jianyi Lin; Jim Yang Lee
No coin nor oath required. For personal study only.
Carbon materials can be easily functionalized using citric acid (CA) treatment. The CA modification of carbon materials is both simple and effective. It requires no prolonged heating, filtration and washing, and produces more functional groups such as carboxyl and hydroxide on CA-modified carbon nanotubes and XC72 carbon blacks than on HNO 3 -H 2 SO 4 oxidized carbon nanotubes and as-purchased XC72. Platinum nanoparticles are deposited on these functionalized carbon materials by means of a microwave-assisted polyol process. The investigations using TEM, XRD, FTIR and TGA indicate that CA modification creates more functional groups and thus deposits more Pt nanoparticles with smaller average particle size on the surface of carbon materials. Electrochemical studies of the Pt/C samples for methanol oxidation reveal higher activity for Pt on CA-modified carbon materials. It is therefore considered that this method can find important applications in reducing the cost and improving performance of proton-exchange membrane fuel cells.
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## Abstract In comparison to sulfonated polymers, phosphonic acidβfunctionalized polyelectrolytes possess higher proton conductivity at elevated temperatures, improved chemical and thermal stabilities, much lower water swelling, decreased fuel permeability, and enhanced proton conductivities in low