Effects of Core-Shell Interface Structures on ORR Activities: a Model Catalyst Study of Pt/Pd(111). (14th September 2015)

• Record Type: Journal Article
• Authors: Todoroki, Naoto; Bando, Yohe; Watanabe, Hirofumi; Wadayama, Toshimasa
• Is Part Of: ECS transactions. Volume 69:Number 17(2015)
• Page Start: 315
• Page End: 320
• Publication Date: 2015-09-14
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/06917.0315ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : We investigated surface structures and oxygen-reduction reactions (ORR) of Pt–Pd(111) model bimetallic surfaces fabricated by molecular beam epitaxy. The Pt/Pd(111) surfaces were prepared by depositing 0.6-nm-thick Pt on Pd(111) at substrate temperatures of 573 and 673 ( x K-Pt0.6nm –Pd(111), where x = 573 or 673). Reflection high-energy electron diffraction patterns and ultra-high-vacuum scanning tunneling microscopy images revealed that Pt grew epitaxially on the Pd(111) substrate under the deposition conditions selected for the study. However, analysis of low-energy ion scattering results suggested that the Pt and Pd atomic compositions of the topmost surfaces were different for 573K-Pt0.6nm /Pd(111) and 673K-Pt0.6nm /Pd(111). The ORR activities of the 573K-Pt0.6nm /Pd(111) and 673K-Pt0.6nm /Pd(111) surfaces were 6.3 and 3.6 higher than that for Pt(111), respectively. The results indicate that alloy structures near the surface determine the ORR activity of practical Pd@Pt core–shell catalysts.