A versatile approach to processing of high active area pillar coral- and sponge-like Pt-nanostructures. Application to electrocatalysis

A facile electrochemical processing method for Pt-based nanostructures with high surface area and a broad range of possible applications is proposed, based on sacrificial ZnO nanostructures. At first, ZnO-nanorods and nanobelts were grown on a TiO2 terminated steel substrate via a fast wet chemical method and subsequently sputter coated with an ultra-thin gold film to ensure electrical contact. These nanostructured substrates were used as electrodes for Pt electrodeposition. It is shown that ZnO was dissolved while Pt-nanoparticles nucleated and grew, replicating the ZnO nanostructure morphology. In this way we could process closed Pt-nanorods with morphologies reminiscent to pillar coral, and Pt-nanobelts with a sponge-like topology. In comparison to commercial catalysts like Pt/C30, the nanostructures obtained are characterized by higher real surfaces, higher efficiency for methanol electrooxidation and higher resistance to poisoning by carbonaceous species, and so should be promising as electrodes in direct methanol oxidation fuel cells.