Oxygen Reduction Kinetics on Pt Monolayer Shell Highly Affected by the Structure of Bimetallic AuNi Cores

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• 作者：Guangyu Chen ; Kurian A. Kuttiyiel ; Dong Su ; Meng Li ; Chiu-Hui Wang ; David Buceta ; Chunyu Du ; Yunzhi Gao ; Geping Yin ; Kotaro Sasaki ; Miomir B. Vukmirovic ; Radoslav R. Adzic
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：August 9, 2016
• 年：2016
• 卷：28
• 期：15
• 页码：5274-5281
• 全文大小：512K
• 年卷期：0
• ISSN：1520-5002

文摘

We describe pronounced effects of structural changes of the AuNi cores on the oxygen reduction reaction (ORR) activity of a Pt monolayer shell. The study of alloyed AuNi nanoparticles compared with AuNi core–shell structured nanoparticles revealed configurations having different electronic and electrochemical properties. Controlled alloying of Au with Ni was essential to tune the electronic properties of Au interacting with the Pt monolayer shell to achieve suitable adsorption of O₂ on Pt for expediting the ORR. The alloyed AuNi nanoparticles made the Pt shell more catalytically active for the ORR than the core–shell structured AuNi nanoparticles. The Pt monolayer supported on the alloyed AuNi nanoparticles showed the Pt mass and specific activities as high as 1.52 A mg^–1 and 1.18 mA cm^–2, respectively, with almost no loss over 5 000 cycles of stability test. This high ORR activity is ascribed to the role of nonspecific steric configuration of Ni atoms changing the electronic properties of the alloy that affect the oxygen and water interaction with the Pt shell and facilitate increased ORR kinetics.