Metal particle characterization of zeolite-based syngas conversion catalysts
In this study it has been demonstrated that magnetic and chemisorptive techniques can be used to characterize metal speciation in catalysts such as Co/ZSM-5. In particular, the amounts of ion-exchanged cobalt and cobalt external to the zeolite can be estimated. These measurements enable one to intepret the catalytic activity and selectivity of the catalyst. In our attempts to introduce cobalt in cationic form in ZSM-5 we have used a temperature of 90/sup 0/C for exchange with aqueous cobalt nitrate solution. It appears that 0.9 wt % Co can be introduced into ZSM-5 of SiO/sub 2//Al/sub 2/O/sub 3/ = 38 under these circumstances. Co/ZSM-5 samples that were prepared by impregnation at room temperature with cobalt nitrate solution, showed approximately 2.2 wt % Co to be in a form not reducible to metallic cobalt. In earlier work the Co/ZSM-5 samples were subsequently washed with water to yield samples that contained 1.4 to 1.7 wt % Co. It is hence possible that exchange at temperatures lower than 90/sup 0/C would yield samples containing more than 0.9 wt % Co in ion-exchanged form. It is shown in this study that Co/sup 2 +//ZSM-5 can be back-exchanged and reduced to yield metallic cobalt supported on H-ZSM-5. Chemisorption measurements are currently being carried out to determine the degree of dispersion of such samples. The back-exchanged samples are catalytically active in synthesis gas conversion. The method of back-exchange should be generally applicable for preparing metal-zeolite catalysts where it is desirable to free the zeolite of metal cations in order to restore the acidity to its original strength, and to have the metal on the exterior of the zeolite crystallites in a highly dispersed, catalytically active form. 14 refs., 2 figs., 3 tabs.
- Research Organization:
- USDOE Pittsburgh Energy Technology Center, PA; Pennsylvania State Univ., McKeesport (USA). Dept. of Physics; Washington and Jefferson Coll., Washington, PA (USA)
- OSTI ID:
- 5575173
- Report Number(s):
- CONF-840805-29; ON: DE85012220
- Resource Relation:
- Conference: 188. meeting of the American Chemical Society, Philadelphia, PA, USA, 26 Aug 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CATALYSTS
CHEMICAL PREPARATION
COBALT
CATALYTIC EFFECTS
SORPTIVE PROPERTIES
FISCHER-TROPSCH SYNTHESIS
HYDROCARBONS
CHEMICAL REACTION YIELD
SYNTHESIS
HYDROGEN
ADSORPTION ISOTHERMS
CHEMISORPTION
ZEOLITES
CATALYST SUPPORTS
CATIONS
COBALT NITRATES
EXPERIMENTAL DATA
ION EXCHANGE
SYNTHESIS GAS
CHARGED PARTICLES
CHEMICAL REACTIONS
COBALT COMPOUNDS
DATA
ELEMENTS
FLUIDS
GASES
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
ISOTHERMS
MATERIALS
METALS
MINERALS
NITRATES
NITROGEN COMPOUNDS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YIELDS
090121* - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989)