451367 Thermal Stability of Shape-Controlled Pd-Pt Core-Shell Nanoparticles

Wednesday, November 16, 2016: 12:49 PM
Peninsula (Hotel Nikko San Francisco)
Luke T. Roling1, Ahmed Elnabawy1, Madeline Vara2, Xue Wang2, Younan Xia2 and Manos Mavrikakis1, (1)Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, (2)Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA

Thermal Stability of Shape-Controlled Pd-Pt Core-Shell Nanoparticles

Luke T. Rolinga, Ahmed O. Elnabawya, Madeline Varab, Xue Wangb, Younan Xiab, and Manos Mavrikakisa

aDepartment of Chemical & Biological Engineering, University of Wisconsin-Madison, Madison, WI
bDepartment of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA

We recently reported the synthesis and electrocatalytic performance of shape-controlled Pd-Pt core-shell nanoparticles that demonstrated exceptional activity and stability toward the oxygen reduction reaction.1,2 In this presentation, we investigate and explain the durability of these catalysts in high-temperature environments typical of a broader range of catalytic applications. We observe that the cubic and octahedral nanocatalysts are stable to at least 500 °C; interestingly, the core-shell structure and overall particle shape are each deformed at different temperatures in the two catalyst geometries.

Detailed DFT calculations rationalize the observed behaviors, attributing the differences in reconstruction to lower activation energy barriers for metal atom migration from the nanoparticle edges. Calculations also indicate that different concentrations of subsurface vacancies are seeded during nanoparticle synthesis, and that these are responsible for differences in Pd-Pt interdiffusion, which causes disruption of the core-shell structure at elevated temperatures.

1. S. Xie, S.-I. Choi, N. Lu, L. T. Roling, J. A. Herron, L. Zhang, J. Park, J. Wang, M. J. Kim, Z. Xie, M. Mavrikakis, Y. Xia, Nano Letters 2014, 14, 3570
2. J. Park, L. Zhang, S. Choi, L. T. Roling, N. Lu, J. A. Herron, S. Xie, J. Wang, M. J. Kim, M. Mavrikakis, Y. Xia, ACS Nano 2015, 9, 2635.


Extended Abstract: File Not Uploaded