ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

HREM imaging of small Pt clusters dispersed in Y-zeolites (1990)

Pan, M. ; Cowley, J. M. ; Chan, I. Y.

Springer

Catalysis letters 5 (1990), S. 1-11

add to mindlist on the mindlist

Details

ISSN: 1572-879X

Keywords: HREM ; small Pt clusters ; zeolites

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract High resolution electron microscopy (HREM) has been used to study dispersed Pt clusters in NaY- and USY-zeolites. All the samples contained 0.8% Pt and were reduced at temperatures of 300 ° C, 500 ° C and 650 ° C. The size of the Pt clusters ranged from a few å up to ∼ 30 å. When the incident electron beam was sufficiently strong, it caused some of the extremely small metal clusters to sinter. This was usually accompanied by zeolite damage. This in-situ sintering must be taken into consideration when interpreting the particle size distribution results obtained solely by TEM, especially for particles that are smaller than 10 å. The minimum phase contrast imaging condition is demonstrated to be more appropriate than optimum defocus for detecting the extremely small Pt clusters inside the zeolite structures.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00772087

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Stepped surfaces of sapphire (α-Al2O3) with low miller indices (1992)

Ndubuisi, Godfrey C. ; Liu, J. ; Cowley, J. M.

New York, NY [u.a.] : Wiley-Blackwell

Microscopy Research and Technique 21 (1992), S. 10-22

add to mindlist on the mindlist

Details

ISSN: 1059-910X

Keywords: Relationships ; TEM and REM images ; Surface structural features ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Natural Sciences in General

Notes: Oxygen-annealed surfaces of sapphire with low Miller indices ((0001), {1010}, {1120}, {1011}) have been studied in both transmission electron microscopy (TEM) and reflection electron microscopy (REM) configurations. The significance of REM diffraction conditions for the determination of the nature of the step heights is discussed. The relationship between the TEM and REM images is explained. The structural features are those that might be expected from considerations of the atom arrangement in the low Miller index planes. The structural features on the surfaces varied with respect to annealing temperature and surface condition. Thermally stable structures that might appear from consideration of the equilibrium-annealing temperature are proposed.

Additional Material: 8 Ill.