High-angle ADF and high-resolution SE imaging of supported catalyst clusters

Jingyue Liu, J. M. Cowley

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

A high-angle annular detector provides a useful imaging signal for the detection of small metal catalyst clusters in light-element supports. The high-angle annular-dark-field (HAADF) signal is mainly generated by quasi-elastic scattering. The collected signal intensity depends on the atomic number of the scatterer, its amplitude of vibration and the total number of atoms encountered by the probe. This imaging mode can reveal high-Z sensitivity and eliminate most of the diffraction contrast present in low-angle ADF images. In a STEM instrument, secondary electron images with a resolution approaching the probe size ( ∼ 0.5 nm in diameter) can be obtained simultaneously with HAADF images, providing topographic information about the metal catalyst-support system. The combination of a variety of imaging and diffraction techniques available in a STEM instrument can yield important information about the distribution of small metal clusters in the supports, crystallographic relationships between the metal clusters and the support, and morphology as well as chemical compositions of the metal catalyst-support system. Samples of Pt/carbon, Pt/γ-alumina and Pt/NaY zeolite catalysts have been examined. Preliminary results reveal useful information about these catalyst systems.

Original languageEnglish (US)
Pages (from-to)119-128
Number of pages10
JournalUltramicroscopy
Volume34
Issue number1-2
DOIs
StatePublished - 1990

Fingerprint

Catalyst supports
Metals
Imaging techniques
catalysts
high resolution
support systems
metal clusters
Catalysts
Diffraction
metals
Zeolites
Elastic scattering
Aluminum Oxide
probes
light elements
diffraction
imaging techniques
Chemical elements
chemical composition
elastic scattering

ASJC Scopus subject areas

  • Materials Science(all)
  • Instrumentation

Cite this

High-angle ADF and high-resolution SE imaging of supported catalyst clusters. / Liu, Jingyue; Cowley, J. M.

In: Ultramicroscopy, Vol. 34, No. 1-2, 1990, p. 119-128.

Research output: Contribution to journalArticle

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