Metallic cobalt and iron particles in large and medium pore zeolites. Methods of generation and ferromagnetic resonance characterization
Spectroscopic studies utilizing photoacoustic electronic spectroscopy, electron paramagnetic resonance, and ferromagnetic resonance have been made on the formation of (1) Co metal particles from CO(NH/sub 3/)/sub 6//sup 3 +/ exchanged into Y zeolite and (2) Fe metal particles from nonframework Fe/sup 3 +/ ions in an aluminoferrisilicate analogue of ZSM-5 zeolite. Decomposition of the Co(NH/sub 3/)/sub 6//sup 3 +/ complex is accompanied by autoreduction to the Co/sup 2 +/ state, observed by EPR at 7/sup 0/K, but no Co metal is formed. The Co/sup 2 +/ ions migrate from the supercage locations of the parent complexes into the hexagonal prisms and are subsequently very difficult to reduce, even with H/sub 2/ at 823/sup 0/K. High-temperature FMR data suggest that the small amount of Co metal particles which are formed exist with the fcc crystal structure yielding g = 2.17 at 508/sup 0/K, consistent with an empirically calculated value for fcc Co. Hexagonal close packed Co particles are expected to exhibit much larger magnetic anisotropy than was observed. The Fe/sup 3 +/ ions in the medium pore pentasil aluminoferrisilicate zeolite can be reduced to the metallic state following either (a) precipitation of the inclusion compound, Fe/sup III/(Fe/sup II/(CN)/sub 5/(NO)), in the zeolite, or (b) generation of superparamagnetic oxidic ferric ion clusters. High-temperature FMR data establish that smaller Fe particles can be obtained by the latter method.
- Research Organization:
- Argonne National Lab., IL (USA); University of South Florida, Tampa (USA); Northwestern Univ., Evanston, IL (USA)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 6943194
- Report Number(s):
- CONF-8310251-2; ON: DE84011701
- Resource Relation:
- Conference: US-Western Europe regional seminar on metal complex catalysts and metal catalyzed reactions in intracrystalline environments, Brugge, Belgium, 24 Oct 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT IONS
REDUCTION
IRON IONS
AMMINES
COBALT COMPLEXES
ION EXCHANGE
MAGNETIC RESONANCE
PHOTOACOUSTIC SPECTROSCOPY
ZEOLITES
CHARGED PARTICLES
CHEMICAL REACTIONS
COMPLEXES
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
MATERIALS
MINERALS
RESONANCE
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties