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Exceptional high-temperature stability through distillation-like self-stabilization in bimetallic nanoparticles

Nature Materials volume 9, pages 7581 (2010) | Download Citation

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Abstract

Metal nanoparticles with precisely controlled size and composition are highly attractive for heterogeneous catalysis. However, their poor thermal stability remains a major hurdle on the way towards application at realistic technical conditions. Recent progress in this area has focused on nanostructured oxides to stabilize embedded metal nanoparticles. Here, we report an alternative approach that relies on synthesizing bimetallic nanoparticles with precise compositional control to obtain improved high-temperature stability. We find that PtRh nanoparticles with sufficiently high Rh content survive extended calcination at temperatures up to 850 C without significant sintering. For lower Rh content, sacrificial self-stabilization of individual nanoparticles through a distillation-like process is observed: the low-melting-point metal (Pt) bleeds out and the increasing concentration of the high-melting-point metal (Rh) leads to re-stabilization of the remaining nanoparticle. This principle of thermal self-stabilization should be broadly applicable to the development of multi-metallic nanomaterials for a broad range of high-temperature applications.

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Acknowledgements

This work was supported by the National Energy Technology Laboratory’s on-going research under the RDS contract DE-AC26-04NT41817, by the Department of Energy—Basic Energy Science through grant DE-FG02-05ER46233 and by the National Science Foundation through grant CTS-0553365. G.V. gratefully acknowledges a CNG faculty fellowship of the University of Pittsburgh’s Swanson School of Engineering. We thank Z. Liu for technical help with TEM characterizations and the Nanoscale Fabrication and Characterization Facility (NFCF) of the University of Pittsburgh for use of the electron microscopy facility.

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Affiliations

  1. National Energy Technology Laboratory, US Department of Energy, PO Box 10940, Pittsburgh, Pennsylvania 15236, USA

    • Anmin Cao
    •  & Götz Veser
  2. Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA

    • Anmin Cao
    •  & Götz Veser

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Contributions

A.C. carried out all experimental work, including material synthesis, characterization and catalytic tests. G.V. designed and supervised the research programme. Both contributed to data analysis, discussion and writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Götz Veser.

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DOI

https://doi.org/10.1038/nmat2584

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