Dissolution and redeposition on Pt nanoparticles under electrochemical conditions

We present a Schottky-type model describing Pt 2 + dissolution and redeposition on Pt nanoparticles in polymer electrolyte fuel cells. The charge transfer is considered to occur near the surface of nanoparticles so that the potential barrier for the reaction is formed by the double-layer potential and the image interaction. With increasing electrode potential, the transfer coefficient for dissolution is found to decrease from 0.6–0.7 down to 0.3–0.4. Its dependence on the effective dielectric constant of the double layer is appreciable while the dependence on the particle size is weak.