Ta <inf>2</inf> O <inf>5</inf> templated growth of droplet-like platinum particles by potentiodynamic polarization of tantalum in aqueous solution of hexachloroplatinic acid

Abstract

By potentiodynamic polarization of mechanically polished tantalum in a diluted aqueous solution of hexachloroplatinic acid, droplet-like platinum microparticles were electrodeposited, embedded into the simultaneously formed Ta 2 O 5 film. The roughness factor of platinum of 31 was achieved. Within the potential region of both hydrogen and oxygen underpotential deposition, in both acidic and alkaline solutions, the composite Pt/Ta 2 O 5 electrode displayed an excellent electrochemical response characteristic of smooth polycrystalline platinum. The preparation method applied in this work presents an easy way to obtain an electrode surface combining the behaviour of smooth polycrystalline platinum with the behaviour of microdisc arrays. Its electrocatalytic effectiveness was demonstrated for an oxygen reduction reaction in alkaline solutions. © 2005 Elsevier B.V. All rights reserved.