Shape-controlled fabrication of platinum electrocatalyst by pulse electrodeposition

Platinum catalysts were pulse electrodeposited on carbon black/Nafion^® substrates in solutions with or without shape-control agents such as polyethylene glycol (PEG-10000) or lead (II) acetate (LA). The SEM and electrochemical measurements showed that the morphology, microstructure and electrocatalytic activities of the platinum deposits changed by using different additives. The morphology of Pt evolved from spherical clusters to clump-like crystal aggregations and elongated leaf-like flake clusters by using PEG-10000 and LA, respectively. For the Pt catalyst deposited by introducing PEG-10000, its active surface area and electrocatalytic activities towards methanol electro-oxidation and oxygen electro-reduction were remarkably improved. The possible mechanism for the change of the morphology has been preliminarily discussed.