Gas-Induced Segregation in Pt-Rh Alloy Nanoparticles Observed by in Situ Bragg Coherent Diffraction Imaging

Tomoya Kawaguchi, Thomas F. Keller, Henning Runge, Luca Gelisio, Christoph Seitz, Young Yong Kim, Evan R. Maxey, Wonsuk Cha, Andrew Ulvestad, Stephan O. Hruszkewycz, Ross Harder, Ivan A. Vartanyants, Andreas Stierle, Hoydoo You

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Abstract

Bimetallic catalysts can undergo segregation or redistribution of the metals driven by oxidizing and reducing environments. Bragg coherent diffraction imaging (BCDI) was used to relate displacement fields to compositional distributions in crystalline Pt-Rh alloy nanoparticles. Three-dimensional images of internal composition showed that the radial distribution of compositions reverses partially between the surface shell and the core when gas flow changes between O2 and H2. Our observation suggests that the elemental segregation of nanoparticle catalysts should be highly active during heterogeneous catalysis and can be a controlling factor in synthesis of electrocatalysts. In addition, our study exemplifies applications of BCDI for in situ 3D imaging of internal equilibrium compositions in other bimetallic alloy nanoparticles.

Original languageEnglish
Article number246001
JournalPhysical review letters
Volume123
Issue number24
DOIs
Publication statusPublished - 2019 Dec 13

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Kawaguchi, T., Keller, T. F., Runge, H., Gelisio, L., Seitz, C., Kim, Y. Y., Maxey, E. R., Cha, W., Ulvestad, A., Hruszkewycz, S. O., Harder, R., Vartanyants, I. A., Stierle, A., & You, H. (2019). Gas-Induced Segregation in Pt-Rh Alloy Nanoparticles Observed by in Situ Bragg Coherent Diffraction Imaging. Physical review letters, 123(24), [246001]. https://doi.org/10.1103/PhysRevLett.123.246001