Pore structure of thermally treated goethite (α-FeOOH)
The thermal decomposition of synthetic α-FeOOH in air has been studied by X-ray powder diffraction (XRD), IR spectroscopy, transmission electron microscopy, and nitrogen adsorption. Three stages may be differentiated during the course of the reaction: (i) 200-250°C; slit-shaped micropores of nearly equal width, about 1.4 nm, are formed along the elongated direction of the lath-shaped acicular microcrystals of the hematite products, the highest surface area is obtained on a α-FeOOH decomposed at 250°C; (ii) 300-600°C; an internal sintering occurs within the microcrystals transforming the micropores into closed spherical mesopores with the consequent significant decrease in surface area; and (iii) above 600°C; interparticle sintering takes place and no valuable porosity is detected. Particle shape effects are shown to be the reason for the differences in the IR spectra and for the nonuniform broadening of the XRD peaks observed in the hematite products.
| Main Authors: | , , , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Academic Press
1983-4
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| Online Access: | http://hdl.handle.net/10261/63584 |
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