Pd-Pt Bimetallic Nanodendrites with High Activity for Oxygen Reduction

• Published in: Science (American Association for the Advancement of Science) Vol. 324; no. 5932; pp. 1302 - 1305
• Main Authors: Lim, Byungkwon, Jiang, Majiong, Camargo, Pedro H.C, Cho, Eun Chul, Tao, Jing, Lu, Xianmao, Zhu, Yimei, Xia, Younan
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 05.06.2009; The American Association for the Advancement of Science
• Subjects: 30 DIRECT ENERGY CONVERSION; AQUEOUS SOLUTIONS; Catalysis; CATALYSTS; Cross-disciplinary physics: materials science; rheology; Dendrites; Electrochemistry; Exact sciences and technology; Fuel cells; Kinetics; MATERIALS SCIENCE; Metal Nanoparticles - chemistry; MORPHOLOGY; Nanocrystals; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; NANOSTRUCTURES; Oxidation; Oxidation-Reduction; OXYGEN; Oxygen - chemistry; Palladium - chemistry; Physics; Platinum - chemistry; PROTON EXCHANGE MEMBRANE FUEL CELLS; Room temperature; SEEDS; SURFACE AREA; Surface areas; transmission electron microscope; Exchange; Aqueous solutions; Platinum; Fuel cells; Catalysis; Nanostructures; Nanocrystal
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1170377

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 a half times more active on the basis of 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.