Electrodeposited platinum microparticles in a sulfonate-polyaniline film for the electrosorption of methanol and sorbitol

The electrodeposition of platinum microparticles into a 2,5-diaminobenzenesulfonic acid-modified polyaniline (SPANI) film on IrO₂ electrodes and its electrosorption for methanol and sorbitol, respectively, are described. Electrodeposited platinum microparticles under constant potential are dispersed in a three-dimensional array in porous SPANI films as evidenced by Auger electron spectroscopy (AES). Characterization of the Pt/SPANI/IrO₂ electrodes by SEM shows that the deposition procedure yields spherical catalyst particles. X-ray photoelectron spectroscopy (XPS) results show that there is not significant variability in the binding energy of carbon and nitrogen, respectively, on SPANI chains for different Pt loadings. For catalyst loading of ca. 7 mg cm^-2 deposited at -200 mV, the electrosorption coverages of sorbitol are always greater than that of methanol about 15%. In comparison to sorbitol, the readsorption of methanol on Pt catalyst site occurs significantly during electrosorption.