| 초록 |
Pt-Ni alloy nanocrystals with Pt-enriched shell were prepared by chemical dissolution of Ni. The changes in electronic and geometric structure of the alloy nanoparticles at surface were elucidated from electrochemical surface area, potential of zero total charge, and relative surface roughness. It was found that sulfuric acid-treated Pt-Ni catalyst showed the lower activity and durability despite its higher surface Pt concentration and alloying level. In this presentation, we propose new electrochemical method of calculating relative surface roughness by measuring adsorption/desroption behaviors of carbon monoxide and carbon dioxide molecules. In this work, it was revealed that surface roughness plays a critical role to improve electrochemical performance of Pt-Ni alloy catalysts with Pt-rich surfaces. In addition, combination of the displacement experiments can be employed as an efficient probe for estimating the surface roughness change of Pt-based bimetallic nanoparticles.
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