Potentiostatic Electrodeposition of Pt Nanoparticles on Carbon Black

Abstract

Simple potentiostatic electrodeposition of platinum nanoparticles was performed on carbon black to prepare a carbon-supported Pt catalyst for polymer electrolyte fuel cells. The effect of ethylene glycol (EG) as an additive, deposition potential, and pH on the size and content of the electrodeposited Pt particles in the carbon powder was examined. Compared with the particles electrodeposited from a solution without EG, those with EG were smaller and dispersed well on the carbon. The electrodeposition at a more negative potential produced smaller particles. However, when the deposition potential was more negative than the equilibrium potential for H+/H2, Pt content higher than 30 wt % could not be obtained. In contrast, when the deposition potential was more positive than the equilibrium potential of H+/H2, the Pt content could be controlled by the amount of electrical charge, and increased up to 40 wt %. The electrodeposition from an alkaline solution yielded Pt particles with a mean size of 4 nm, smaller than those obtained from a standard acidic solution.