ELECTRODEPOSITED PLATINUM MICROPARTICLES IN SULFONATE-POLYANILINE FILM FOR THE ELECTROSORPTION OF METHANOL AND SORBITOL

The electrodeposition of platinum microparticles into a 2,5-diaminoben zenesulfonic acid-modified polyaniline (SPANI) film on IrO2 electrodes and its electrosorption for methanol and sorbitol, respectively, are described. Electrodeposited platinum microparticles under constant pot ential are dispersed in a three-dimensional array in porous SPANI film s as evidenced by Auger electron spectroscopy (AES). Characterization of the Pt/SPANI/IrO2 electrodes by SEM shows that the deposition proce dure yields spherical catalyst particles. X-ray photoelectron spectros copy (XPS) results show that there is not significant variability in t he binding energy of carbon and nitrogen, respectively, on SPANI chain s for different Pt loadings. I:or catalyst loading of ca. 7 mg cm(-2) deposited at -200 mV, the electrosorption coverages of sorbitol are al ways greater than that of methanol about 15%. In comparison to sorbito l, the readsorption of methanol on Pt catalyst site occurs significant ly during electrosorption. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.