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Electrochemical Probing on Structural Changes of Surface Composition and Geometry of Ptni Nanoparticles with Pt-Enriched Surface

Monday, 29 May 2017: 12:10
Grand Salon B - Section 7 (Hilton New Orleans Riverside)
T. Y. Jeon (Pohang Accelerator Laboratory), S. K. Kim (Korea Institute of Energy Research), and H. H. Lee (Pohang Accelerator Laboratory)
Alloying Pt with M (M = Fe, Co, Ni, Cu, etc) has been extensively studied for increasing the oxygen reduction rate owing to the decreased bond strength of hydroxyl to Pt. Formation of Pt-enriched surface on the Pt-M alloy core can enhance both activity and durability, which generates several unique features that make it the most promising candidate for active and durable ORR catalyst, such as lower d-band center and consequent weaker bond strength of oxygen-containing adsorbates, and increased dissolution potential of surface Pt.

Our recent study on PtNi bimetallic nanoparticles with Pt-enriched surface for oxygen reduction reaction (ORR) will be presented with introducing conceptual understanding of electronic modification induced by the formation of Pt skin on PtM alloy.1 In particular, it will be discussed that the electrochemical properties, which were obtained from CO and reduced COadlayer oxidation measurements before and after potential cycling under ORR conditions, provide us important informations for estimating the surface electronic and geometric states of pure Pt, PtNi, and Pt-enriched PtNi.

1. Jeon, T.-Y., Kim, S. K., Pinna, N., Sharma, A., Park, J., Lee, S. Y., Lee, H. C., Kang, S.-W., Lee, H.-K., Lee, H. H. Chem. Mater. 2016, 28, 1879-1887.