Highly Crystalline Multimetallic Nanoframes with Three-Dimensional Electrocatalytic Surfaces

• Published in: Science (American Association for the Advancement of Science) Vol. 343; no. 6177; pp. 1339 - 1343
• Main Authors: Chen, Chen, Kang, Yijin, Huo, Ziyang, Zhu, Zhongwei, Huang, Wenyu, Xin, Huolin L., Snyder, Joshua D., Li, Dongguo, Herron, Jeffrey A., Mavrikakis, Manos, Chi, Miaofang, More, Karren L., Li, Yadong, Markovic, Nenad M., Somorjai, Gabor A., Yang, Peidong, Stamenkovic, Vojislav R.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 21.03.2014; The American Association for the Advancement of Science; AAAS
• Subjects: Age; carbon electrodes; Catalysts; Crystallization; Durability; Electrocatalysis; Electrocatalysts; fuel cells; Materials; MATERIALS SCIENCE; Molecular evolution; nanocrystals; nanoparticles; Nanostructures; Nickel; Platinum; Polyhedrons; Shergottites; Surface chemistry; Three dimensional imaging
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1249061

Control of structure at the atomic level can precisely and effectively tune catalytic properties of materials, enabling enhancement in both activity and durability. We synthesized a highly active and durable class of electrocatalysts by exploiting the structural evolution of platinum-nickel (Pt-Ni) bimetallic nanocrystals. The starting material, crystalline PtNi3 polyhedra, transforms in solution by interior erosion into Pt3Ni nanoframes with surfaces that offer three-dimensional molecular accessibility. The edges of the Pt-rich PtNi3 polyhedra are maintained in the final Pt3Ni nanoframes. Both the interior and exterior catalytic surfaces of this open-framework structure are composed of the nanosegregated Pt-skin structure, which exhibits enhanced oxygen reduction reaction (ORR) activity. The Pt3Ni nanoframe catalysts achieved a factor of 36 enhancement in mass activity and a factor of 22 enhancement in specific activity, respectively, for this reaction (relative to state-of-the-art platinum-carbon catalysts) during prolonged exposure to reaction conditions.