Investigation of thermal stability and reactivity of rh nanoclusters on an ultrathin alumina film

Zhen He Liao, Po Wei Hsu, Ting Chieh Hung, Guan Jr Liao, Zhao Ying Chern, Yu Ling Lai, Li Chung Yu, Yao Jane Hsu, Jeng Han Wang, Peilong Chen, Meng Fan Luo

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1 Citation (Scopus)

Abstract

We studied the structural and morphological evolution of Rh clusters on an ordered ultrathin alumina film grown on NiAl(100) in annealing processes, under ultrahigh vacuum conditions and with various surface probe techniques. The Rh clusters, prepared on vapor deposition of Rh onto the alumina film at 300 K, had an fcc phase and grew in the (100) orientation; the annealing altered the cluster structure little—the lattice parameter decreased by a factor <2%—but the cluster morphology significantly. With elevated temperature, small clusters (diameter ≤1.5 nm) decreased little in size; in contrast, large clusters (diameter ≥2.0 nm) varied in a complex manner—their mean diameter decreased to about 1.5 nm on annealing to 450 K, despite their similar height, while it increased to above 2.0 nm at temperature ≥570 K. This atypical decrease in size was governed predominantly by energetics. Such a reduced size enhanced the total surface area as well as the reactivity of the clusters toward methanol decomposition, so increased the production of D2 (H2) and CO from decomposed methanol-d4 (or methanol). The result implies a higher temperature tolerance for Rh clusters on the alumina film and a practical approach to prepare small Rh clusters with high reactivity.

Original languageEnglish
Article number971
JournalCatalysts
Volume9
Issue number11
DOIs
Publication statusPublished - 2019 Nov

Keywords

  • Al O
  • Methanol decomposition
  • Rh nanoclusters
  • Size effect

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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  • Cite this

    Liao, Z. H., Hsu, P. W., Hung, T. C., Liao, G. J., Chern, Z. Y., Lai, Y. L., Yu, L. C., Hsu, Y. J., Wang, J. H., Chen, P., & Luo, M. F. (2019). Investigation of thermal stability and reactivity of rh nanoclusters on an ultrathin alumina film. Catalysts, 9(11), [971]. https://doi.org/10.3390/catal9110971