Skip to main content
SpringerLink
Log in

Behavior of Pt Atoms on Oxide Supports During Reduction Treatments at Elevated Temperatures, Characterized by Aberration Corrected Stem Imaging

  • Published:
Catalysis Letters Aims and scope Submit manuscript

Abstract

Aberration-corrected scanning transmission electron microscopy at the sub-Ångström resolution allows imaging the structure of catalytic materials at the single atom level and permits fundamental studies of the behavior of heavy metal catalytic species as a result of elevated temperature gas-treatments. The present study is aimed at understanding the development of clusters and nanoparticles of Pt on γ-alumina during reduction treatments of a pre-oxidized highly dispersed catalyst. A special built ex situ reactor and a specimen holder allowing cyclic anaerobic transfer between the reactor and microscope were used for the study. The number of atoms in a nascent cluster can be determined along with the general shape of the cluster. Reduction experiments without air exposure of the sample showed that although clusters are formed at 500 °C, many Pt atoms are not associated with the cluster and are still dispersed on the catalyst support. After a 700 °C reduction, all of the Pt atoms are associated with the clusters. Movement of the clusters on the catalyst support is different depending upon the catalyst support.

Graphical Abstract

Aberration-corrected scanning transmission electron microscopy at the sub-Ångström resolution allows imaging the structure of catalytic materials at the single atom level and permits fundamental studies of the behavior of heavy metal catalytic species as a result of elevated temperature gas-treatments. The present study is aimed at understanding the development of clusters and nanoparticles of Pt on γ-alumina during reduction treatments of a pre-oxidized highly dispersed catalyst. A special built ex situ reactor and a specimen holder allowing cyclic anaerobic transfer between the reactor and microscope were used for the study. The number of atoms in a nascent cluster can be determined along with the general shape of the cluster. Reduction experiments without air exposure of the sample showed that although clusters are formed at 500 °C, many Pt atoms are not associated with the cluster and are still dispersed on the catalyst support. After a 700 °C reduction, all of the Pt atoms are associated with the clusters. Movement of the clusters on the catalyst support is different depending upon the catalyst support.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Similar content being viewed by others

References

  1. Treacy MMJ, Howie A, Wilson CJ (1978) Phil Mag A38:569

    Google Scholar 

  2. Treacy MMJ, Rice SJ (1989) J Microsc 156:211

    Article  CAS  Google Scholar 

  3. Bradley SA, Cohn MJ, Pennycook SJ (1994) Microsc Res Tech 28:427

    Article  CAS  Google Scholar 

  4. Liu J (2004) Microsc Microanal 10:55

  5. Rice SB, Koo YJ, Disko MM, Treacy MMJ (1990) Ultramicroscopy 34:108

    Article  CAS  Google Scholar 

  6. Nellist PD, Pennycook SJ (1996) Science 274:413

    Article  CAS  Google Scholar 

  7. Blom DA, Bradley SA, Sinkler W, Allard LF (2006) Microsc Microanal 12:50

    Article  Google Scholar 

  8. Uzum A, Ortalan V, Browning ND, Gates BC (2009) Chem Commun 21(31):4657

    Article  Google Scholar 

  9. Sun J, Chi M, Lobo-Lapidus RJ, Mehraeen S, Browning ND, Gates BC (2009) Langmuir 25:10754

    Article  CAS  Google Scholar 

  10. Shannon MD, Lok CM, Casci JL (2007) J Catal 249:41

    Article  CAS  Google Scholar 

  11. Sanchez SI, Small MW, Sivaramakrishnan S, Wen JG, Zuo JM, Nuzzo RG (2010) Anal Chem 82:2599

    Article  CAS  Google Scholar 

  12. Allard LF, Ailey KS, Datye AK, Bigelow WC (1997) Proc Microsc Microanal 595

  13. Jackson SD, Willis J, McLellan GD, Webb G, Keegan MBT, Moyes RB, Simpson S, Wells PB, Whyman R (1993) J Catal 139:191

    Article  CAS  Google Scholar 

  14. Poltorak OM, Boronin VS (1966) Russ J Phys Chem 40:1436

    Google Scholar 

  15. Vaarkamp M, Miller JT, Modica FS, Koningsberger DC (1996) J Catal 163:294

    Article  CAS  Google Scholar 

  16. Vila F, Rehr JJ, Kas J, Nuzzo RG, Frenkel AI (2008) Phys Rev B 78:121404

    Article  Google Scholar 

  17. Dayte AK, Kalakkad DS, Chao MH (1995) J Catal 155:148

    Article  Google Scholar 

  18. Tauster SJ, Fung SC (1978) J Catal 55:29

    Article  CAS  Google Scholar 

  19. Gubbens A, Barfels M, Trevor C, Twesten R, Mooney P, Thomas P, Menon N, Kraus B, Mao C, McGinn B (2010) Ultramicroscopy 110:962

    Article  CAS  Google Scholar 

  20. Gallezot P, Leclercq C, Barbier J, Marecot P (1989) J Catal 116:164

    Article  CAS  Google Scholar 

Download references

Acknowledgements

Microscopy research at the Oak Ridge National Laboratory High Temperature Materials Laboratory was sponsored by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. The authors also thank the University of Wisconsin-Madison for the use of the Titan 80-300 aberration corrected electron microscope.

Author information

Authors and Affiliations

  1. UOP, LLC a Honeywell Company, Des Plaines, IL, USA

    Steven A. Bradley & Wharton Sinkler

  2. EM Center, University of South Carolina, Columbia, SC, USA

    Douglas A. Blom

  3. Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA

    Wilbur Bigelow

  4. Materials Science and Engineering, University of Wisconsin – Madison, Madison, WI, USA

    Paul M. Voyles

  5. Oak Ridge National Laboratory, Oak Ridge, TN, USA

    Lawrence F. Allard

Authors
  1. Steven A. Bradley
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Wharton Sinkler
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Douglas A. Blom
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Wilbur Bigelow
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Paul M. Voyles
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Lawrence F. Allard
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Steven A. Bradley.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bradley, S.A., Sinkler, W., Blom, D.A. et al. Behavior of Pt Atoms on Oxide Supports During Reduction Treatments at Elevated Temperatures, Characterized by Aberration Corrected Stem Imaging. Catal Lett 142, 176–182 (2012). https://doi.org/10.1007/s10562-011-0756-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10562-011-0756-2

Keywords

Search

Navigation