SURFACE-DIFFUSION LIMITED DESORPTION OF IODINE ON A PLATINUM-ELECTRODE

We employed cyclic voltammetry to monitor iodine desorption from a pla tinum electrode, and the uptake of iodine on an iodine-free platinum s urface made available through a dedicated cell geometry and electrode immersion procedures. Within the experimental setting, iodine adsorpti on takes place either on the bottom half of the same working electrode or on a second, indicator electrode. The rate of iodine desorption is electrode potential dependent and is much higher when desorption occu rs from the half I-covered vs. the fully I-covered working electrode. We exclude the possibility of long-range diffusion of iodine on platin um to account for the data, and conclude that 2D diffusion may contrib ute to the accelerated desorption process by allowing iodine to decomp ress before it leaves the surface to solution.