Nanostructured catalyst with hierarchical porosity and large surface area for on-chip fuel cells

This communication reports the synthesis of mesoporous Pd-Co dendrites with both a unique hierarchical porosity and a large surface area by the combination of electrodeposition and dealloying. The resultant mesoporous dendrites consist of microparticles with a diameter of a few hundred nanometers, and the particles have mesopores with around 10 nm width. The mesoporous dendrites are found to be Pd₈Co₂, to be composed of pure Pd crystalline phases and amorphous Pd-Co phases, and to be covered with Pd-skin layers. This catalyst exhibits a high activity in the oxygen reduction reaction. Thus, this novel catalyst is attractive as a catalyst for on-chip fuel cells, which require catalysts to be deposited precisely onto tiny current collectors.