Structure and dispersion of pyrrhotite catalysts derived from binary ferrihydrites
- Univ. of Kentucky, Lexington, KY (United States); and others
Previously, we have shown that impurity anions chemisorbed at the surface of binary ferrihydrites can effectively inhibit particle agglomeration at elevated temperatures in air. Under direct coal liquefaction conditions (DCL) in the presence of sulfur, the binary ferrihydrite phase converts to pyrrhotite (Fe{sub 1-x}S). Transmission electron micrographs show that the pyrrhotite phase derived from binary ferrihydrites under DCL conditions is much better dispersed (average particle diameter {approximately}200 {Angstrom}) than the pyrrhotite derived from pure ferrihydrite (average diameter of {approximately}1000 {Angstrom}). In addition, Mossbauer spectroscopy shows that the pyrrhotite phases from binary ferrihydrites contain more Fe vacancies than those derived from pure ferrihydrites; that is, a larger x value in Fe{sub 1-x}S. These findings explain the improved coal liquefaction activity obtained from binary ferrihydrites.
- OSTI ID:
- 126511
- Report Number(s):
- CONF-950402--
- Country of Publication:
- United States
- Language:
- English
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