Ultrahigh methanol electro-oxidation activity from gas phase synthesized palladium nanoparticles optimized with three-dimensional carbon nanostructured supports

Pd nanoparticles with a mean diameter of 6.7   nm are prepared by gas phase cluster beam deposition. The Pd nanoparticle films exhibit excellent catalytic activity and stability for methanol oxidation. 3D hybrid nanostructures combined with multi-walled carbon nanotubes and few-layer graphene sheets are used as supports to further enhance the methanol electro-oxidation activity of the Pd nanoparticle catalysts by a factor of more than 2.7. The catalytic activity towards methanol electro-oxidation is characterized with cyclic voltammetry measurements. An ultrahigh electrochemical active surface area (ECSA) as large as 311   m 2   g −1 pd and a mass specific current corresponding to methanol oxidation levels as high as 4038   mA   mg −1 pd are realized. These results can be attributed to the high electrochemical activity of the Pd nanoparticles and the unique conductive structure of the multi-walled carbon nanotubes/few-layer graphene sheets.