Electrocatalytic properties of hollow coral-like platinum mesocrystals.

Controlling the morphology and size of Pt nanostructures can provide a great opportunity to improve their electrocatalytic properties and durability toward methanol oxidation. We successfully synthesized well-defined hollow coral-like Pt mesocrystals via a facile replacement reaction, using hierarchically structured Ag nanoparticles as the template. The as-synthesized coral-like Pt mesocrystals had hollow structures composed of porous walls that were 5-7 nm thick, which were constructed from numerous pores (~2 nm) and small (~5 nm) Pt nanoparticle building units. These hollow and porous structures exhibited large electrochemical surface areas. The Pt mesostructures that have single-crystal inherence as well as hollow and porous features possess improved performance with respect to electrocatalytic activity (2.72 mA/cm(2) at peak potential, which is 2.1 times greater than that of Pt black) and durability toward methanol oxidation.