Characterization of rhodium species in Na-X zeolite by electron spin resonance and electron spin echo modulation analyses

Journal Article · Thu Jan 16 04:00:00 EST 1986 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100274a012· OSTI ID:5890806

Goldfarb, D; Kevan, L

Rh(II) species are formed in X zeolite by heating in flowing oxygen. The various species formed after activation at various temperatures, rehydration, and adsorption of various molecules are characterized by electron spin resonance (ESR) and electron spin echo modulation (ESEM) experiments. Two dominant species, termed A and C, are studied in detail. Species A is generated at lower activation temperature than is species C. At intermediate activation temperatures the total Rh spin concentration decreases which is attributed to Rh dimer formation. At higher activation temperatures the total Rh spin concentration increase is consistent with dimer decomposition. Species A is suggested to be located in the ..beta..-cage and species C in the hexagonal prisms of the zeolite X structure based on interaction distances with adsorbates and on the effect of O/sub 2/ on broadening the ESR lines. Rather large distances to water, methanol, and other adsorbates are obtained from the ESEM measurements which suggest that these Rh species are not directly coordinated to the adsorbates. Complete rehydration generates other Rh species which show shorter distances to water characteristic of direct coordination. 33 references, 8 figures, 4 tables.

• Research Organization: Univ. of Houston, TX
• OSTI ID: 5890806
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:2; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

090121 -- Hydrocarbon Fuels-- Chemical Synthesis-- (1976-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACOUSTIC ESR
ADSORPTION
ALKALI METAL COMPOUNDS
CATIONS
CHARGED PARTICLES
DATA
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HEAVY WATER
HIGH TEMPERATURE
HYDRATION
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
LOW TEMPERATURE
MAGNETIC RESONANCE
MATERIALS
MEDIUM TEMPERATURE
MINERALS
NUMERICAL DATA
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
RESONANCE
RHODIUM COMPOUNDS
SODIUM COMPOUNDS
SOLVATION
SORPTION
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
WATER
ZEOLITES