Submitted on December 30, 2008
Accepted on April 9, 2009
Pd-Pt Bimetallic Nanodendrites with High Activity for Oxygen Reduction
Byungkwon Lim 1, Majiong Jiang 2, Pedro H. C. Camargo 1, Eun Chul Cho 1, Jing Tao 3, Xianmao Lu 1, Yimei Zhu 3, Younan Xia 1*
1 Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA.
2 Department of Chemistry, Washington University, St. Louis, MO 63130, USA.
3 Condensed Matter Physics & Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
* To whom correspondence should be addressed.
Younan Xia , E-mail: xia{at}biomed.wustl.edu
Controlling the morphology of Pt nanostructures can provide a great opportunity to improve their catalytic properties and increase their activity on a mass basis. We synthesized Pd-Pt bimetallic nanodendrites consisting of a dense array of Pt branches on a Pd core by reducing K2PtCl4 with L-ascorbic acid in the presence of uniform Pd nanocrystal seeds in an aqueous solution. The Pt branches supported on faceted Pd nanocrystals exhibited relatively large surface areas and particularly active facets toward the oxygen reduction reaction (ORR), the rate-determining step in a proton-exchange membrane fuel cell. The Pd-Pt nanodendrites were two and half times more active based on equivalent Pt mass for the ORR than the state-of-the-art Pt/C catalyst and five times more active than the first-generation, supportless Pt-black catalyst.
