Fabrication of Pd-Ni/Au nanoshelled microsphere array for electrocatalytic oxidation of methanol

Pd-Ni/Au nanoshelled microsphere arrays with different Pd-Ni atomic ratios were successfully synthesized using the etched monolayer colloidal spheres as templates. Morphology and composition characterizations indicated that the prepared products consisted of polystyrene cores of Au and Pd-Ni metallic nanoshells with an overall diameter of 450 nm. Electrochemical measurements in an alkaline solution showed that the Pd-Ni/Au catalyst with Pd:Ni = 4:1 atomic ratio demonstrated an optimal catalytic activity with the peak current of 59.4 mA.cm(-2), the lower oxidation peak potential and the higher stability. These results could be ascribed to the enhanced surface area which increased the number of electrocatalytic active sites, and the electronic interaction between Pd and Ni. This work provides new opportunities for the rational design of microsphere array catalysts for enhancing the catalytic performance in fuel cells.