Seminars

  • 3D Reconstruction of Pt nanoparticle in Operando Condition using Bragg Coherent X-ray Diffraction Imaging

  • Speaker : 김영용 박사/Kim Young Yong
    Affiliation : Deutsches Elektronen-Synchrotron(DESY)
    Date : September 11, 2018 2:00 PM
    Place : Buliding 110 Room N102
    Contact : noejung@unist.ac.kr
    Host : Prof.Noejung Park
  • Abstract

  • We aim to follow changes in the shape, atomic structure and spatial configuration of Pt nanoparticles during catalytic CO and CO/O2 (2:1 ratio) oxidation under continuous gas flow using coherent X-ray diffraction. These structural properties are directly related to catalytic activity and deactivation, which remains crucial for the design of future stable industrial catalyst materials with extended lifetimes. In this experiment, we investigated substrate-supported a single Pt nanoparticle, grown by evaporation on (100)-oriented STO single crystal surfaces using Bragg Coherent Diffraction Imaging (BCDI) in a 8.5 keV energy X-ray beam focused to 150 nm × 300 nm. After measuring 3D Bragg diffraction under Ar, CO and CO/O2 (2:1 ratio) conditions, 3D Pt nanoparticles were successfully reconstructed using phase retrieval algorithm [1-3]. Therefore, we were able to track subtle strain changes of the Pt nanoparticle during catalytic reactions under mild conditions.

     

    References

    [1] R.W.Gerchberg, W.O. Saxton, Optic 35, 237 (1972).

    [2] J. R. Fienup, Appl. Opt. 21, 2758–2769 (1982).

    [3] D. Dzhigaev, J. Opt. 18, 064007 (2016).