Synthesis and electro-catalytic activity of Pt-Co nanoflowers

The study of metallic nanoflowers has attracted more and more attention because of their larger surface areas and active sites, which could be applied for surface-sensitive areas. Despite these excellent characteristics, it is still very hard to synthesize noble metal nanoflowers as the flower-like structure is apt to change into some more stable shapes which are covered by lower energy surfaces. In this study, Pt-Co nanoflowers were successfully synthesized by a two-step method via the reaction between Co nanoparticles and Pt precursor. From the transmission electron microscopy (TEM) images, it could be seen clearly that the products possessed a flower-like nanostructure. The morphology of the final products depended on a number of parameters, such as the reaction time and the reaction temperature. Based on the experimental results and theoretical calculation, the formation of nanoflowers could be attributed to the galvanic replacement reaction between Co nanoparticles and Pt precursor. In addition, the electrochemical catalytic activity of Pt-Co nanoflowers toward methanol oxidation was also evaluated in comparison with that of commercial Pt black. Owing to the special structure, the electro-catalytic activity and stability of Pt-Co nanoflowers were much better than those of commercial Pt black.