Gold-copper nanoparticles: Nanostructural evolution and bifunctional catalytic sites

Jun Yin, Shiyao Shan, Lefu Yang, Derrick Mott, Oana Malis, Valeri Petkov, Fan Cai, Mei Shan Ng, Jin Luo, Bing H. Chen, Mark Engelhard, Chuan Jian Zhong

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Understanding of the atomic-scale structure is essential for exploiting the unique catalytic properties of any nanoalloy catalyst. This report describes novel findings of an investigation of the nanoscale alloying of gold-copper (AuCu) nanoparticles and its impact on the surface catalytic functions. Two pathways have been explored for the formation of AuCu nanoparticles of different compositions, including wet chemical synthesis from mixed Au- and Cu-precursor molecules, and nanoscale alloying via an evolution of mixed Au- and Cu-precursor nanoparticles near the nanoscale melting temperatures. For the evolution of mixed precursor nanoparticles, synchrotron X-ray-based in situ real-time XRD was used to monitor the structural changes, revealing nanoscale alloying and reshaping toward an fcc-type nanoalloy (particle or cube) via a partial melting-resolidification mechanism. The nanoalloys supported on carbon or silica were characterized by in situ high-energy XRD/atomic pair disributoin function (PDF) analyses, revealing an intriguing lattice "expanding-shrinking" phenomenon depending on whether the catalyst is thermochemically processed under an oxidative or reductive atmosphere. This type of controllable structural changes is found to play an important role in determining the catalytic activity of the catalysts for carbon monoxide oxidation reaction. The tunable catalytic activities of the nanoalloys under thermochemically oxidative and reductive atmospheres are also discussed in terms of the bifunctional sites and the surface oxygenated metal species for carbon monoxide and oxygen activation.

Original languageEnglish
Pages (from-to)4662-4674
Number of pages13
JournalChemistry of Materials
Volume24
Issue number24
DOIs
Publication statusPublished - 2012 Dec 21
Externally publishedYes

Keywords

  • CO oxidation
  • catalysts
  • gold-copper nanoalloys
  • molecule-solid duality
  • nanoparticles
  • thermochemical processing

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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    Yin, J., Shan, S., Yang, L., Mott, D., Malis, O., Petkov, V., Cai, F., Shan Ng, M., Luo, J., Chen, B. H., Engelhard, M., & Zhong, C. J. (2012). Gold-copper nanoparticles: Nanostructural evolution and bifunctional catalytic sites. Chemistry of Materials, 24(24), 4662-4674. https://doi.org/10.1021/cm302097c