ISSN:
1572-879X
Keywords:
Monolayer dispersion
;
iron oxide on alumina
;
Mössbauer spectroscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract XRD and Mössbauer spectroscopy studies show that Fe2O3/γ-Al2O3 made by impregnation-calcination method may have monolayer dispersed Fe2O3 and α-Fe2O3 crystallites. There is a threshold monolayer dispersion capacity. If the Fe2O3 loading is lower than the threshold, the Fe2O3 will disperse on the surface of γ-Al2O3 as a monolayer, then the sample will give an XRD pattern with no crystalline Fe2O3 peaks and a Mössbauer spectrum of a doublet with large quadruple splitting (1.11 mm/s). When the Fe2O3 loading is higher than the threshold, in addition to the monolayer dispersed Fe2O3, crystalline α-Fe2O3 will appear, then the sample will give an XRD pattern with crystalline α-Fe2O3 peaks and a Mössbauer spectrum with a quadrupole splitting doublet superimposed on a magnetic splitting sextuplet. Monolayer dispersion capacity obtained by quantitative XRD phase analysis and Mössbauer spectra analysis are consistent with each other, having the same value of 0.052 g Fe2O3/100 m2 α-Al2O3 surface.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00770996
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