The Pt-Ni and Pt-Co nanoparticles covered with a Pt skin layer were prepared by the double potential step electrolysis (DPSE), which composed of potential steps for electrodeposition of the Pt-Ni and Pt-Co alloy and the following selective dissolution of the Ni and Co component, respectively. With this method, the Pt alloy nanoparticles covered with a Pt skin layer could be prepared just in one process, and the composition and size of the Pt alloy nanoparticles could be easily controlled by changing the electrode potential and plating bath composition. Both the nanoparticles by the DPSE exhibited higher corrosion resistance and oxygen reduction reaction (ORR) activity than the Pt nanoparticles even after deterioration test, and the surface contents of them were kept constant around 4 % Co and 8 % Ni measured by XPS over the wide range of Pt alloy compositions, respectively. Comparing the Pt-Ni with Pt-Co nanoparticles, the Pt-Co nanoparticles were found to be more stable than the Pt-Ni nanoparticles, and suggested that a Pt-skin layer on Pt alloy particles had an important role in their performances.
potential step electrolysis, Pt alloy, nanoparticles, corrosion resistance, stability
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