Study of Rh(II) species in Ca-A zeolite by electron spin resonance and electron spin echo modulation spectroscopies

Journal Article · Thu Dec 03 04:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100309a015· OSTI ID:7200149

Goldfarb, D; Kevan, L; Davis, M E; Saldarriaga, C; Rossin, J A

Paramagnetic Rh(II) species generated in RhCa-A after activation and adsorption of various molecules were characterized by electron spin resonance (ESR) and electron modulation (ESEM) spectroscopies. (Rh(NH/sub 3/)/sub 5/Cl)Cl/sub 2/ was incorporated into the zeolite during synthesis. Activation of RhCa-A and RhNa-A at 400-500/sup 0/C either in flowing oxygen or under vacuum did not generate any substantial amount of Rh(II). However, exposure of activated RhCa-A to molecules such as O/sub 2/, CO, H/sub 2/O, NH/sub 3/, CH/sub 3/OH, H/sub 2/, and C/sub 2/H/sub 4/ at room temperature resulted in a considerable increase in the spin concentration which was assigned mainly by Rh(II) species. No such changes were observed in RhNa-A under similar conditions. The formation of the various paramagnetic Rh(II) species, their location within the zeolite structure, and their interaction with adsorbates in terms of the distance and number of interacting molecules as obtained from the ESEM data are discussed. The results are further compared with results previously obtained in Rh-exchanged X and Y zeolites.

• Research Organization: Univ. of Houston, TX (USA)
• OSTI ID: 7200149
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:25; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

090210 -- Alcohol Fuels-- Properties-- (1976-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACOUSTIC ESR
ADSORPTION
ALCOHOLS
ALKENES
AMMONIA
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
ELECTRON SPIN RESONANCE
ELEMENTS
ETHYLENE
HIGH TEMPERATURE
HYDRIDES
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MAGNETIC RESONANCE
MATERIALS
MEDIUM TEMPERATURE
METALS
METHANOL
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PLATINUM METALS
RESONANCE
RHODIUM
SORPTION
TRANSITION ELEMENTS
WATER
ZEOLITES