Tuning the Catalytic Activity of Ru@Pt Core鈥揝hell Nanoparticles for the Oxygen Reduction Reaction by Varying the Shell Thickness

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• 作者：Lijun Yang ; Miomir B. Vukmirovic ; Dong Su ; Kotaro Sasaki ; Jeffrey A. Herron ; Manos Mavrikakis ; Shijun Liao ; Radoslav R. Adzic
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：January 31, 2013
• 年：2013
• 卷：117
• 期：4
• 页码：1748-1753
• 全文大小：285K
• 年卷期：v.117,no.4(January 31, 2013)
• ISSN：1932-7455

文摘

The kinetics of the oxygen reduction reaction (ORR) was investigated in acid solutions on Pt monolayers that were deposited on carbon-supported Ru nanoparticles using the rotating disk electrode technique. The Pt mass and specific ORR activities greatly depend on the number of Pt monolayers, and the optimum activity occurs with two Pt monolayers. Density functional theory calculations showed that Pt overlayers destabilize O* and OH* with respect to pure Pt, leading to more favorable hydrogenation kinetics. However, with only a single Pt overlayer, the destabilization is too much, and O鈥揙 bond breaking becomes rate limiting. Two to three Pt monolayers supported on the Ru core of our nanoparticles lead to increased activity. This work demonstrates that one can modulate the ORR activity of Pt monolayers supported on other metals by eliminating a part of the ligand effect by increasing the thickness of the Pt shell on top of the supporting metal surface.