Carbon monoxide and propene oxidation by iron oxides for auto-emission control
Activities of iron-based materials for the simultaneous total oxidation of CO and C/sub 3/H/sub 6/ were measured under conditions that were typical of automotive operation: space velocity of 35,000 h/sup -1/; temperatures between 373 and 873 K; atmospheric pressure; feed composition of 2.5% CO, 1.7% O/sub 2/, 0.5% H/sub 2/, 0.05% C/sub 3/H/sub 6/, and, optionally, 0.004% SO/sub 2/ in He. In the absence of SO/sub 2/, activity decreased in the order Fe/sub 2/O/sub 3//Al/sub 2/O/sub 3/ > Fe/sub 2/O/sub 3//TiO/sub 2/ approx. Fe/sub 2/O/sub 3/ >> FeSbO/sub 4/ > FePO/sub 4/ > Fe/sub 2/(MoO/sub 4/)/sub 3/. CO and C/sub 3/H/sub 6/ removal followed apparent first-order kinetics and the data showed a compensation law effect. Oxidation was inhibited when SO/sub 2/ was present; temperatures for CO conversion over Fe/sub 2/O/sub 3/ were raised about 160 K, while the comparable rise for C/sub 3/H/sub 6/ oxidation was about 80 K. Inhibition was less with Fe/sub 2/O/sub 3/ on 35 m/sup 2//g TiO/sub 2/ than with Fe/sub 2/O/sub 3/ on 350 m/sup 2//g Al/sub 2/O/sub 3/ or with unsupported 5 m/sup 2//g Fe/sub 2/O/sub 3/. Both FeSbO/sub 4/ and FePO/sub 4/ showed good activity for the conversion of C/sub 3/H/sub 6/, but not of CO, when SO/sub 2/ was absent. Material balances indicate that the partial oxidation product acrolein inhibits CO oxidation over these binary selective oxidation catalysts. Collectively, the data suggest that an inhibitor is created by oxidation of a precursor and its oxidation can be inhibited by the product of another feed component through control of the size of reactive ensembles on the catalyst surface.
- Research Organization:
- Univ. of Delaware, Newark (USA)
- OSTI ID:
- 5218136
- Journal Information:
- J. Catal.; (United States), Vol. 110:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
33 ADVANCED PROPULSION SYSTEMS
54 ENVIRONMENTAL SCIENCES
CARBON MONOXIDE
OXIDATION
CATALYST SUPPORTS
PERFORMANCE TESTING
IRON OXIDES
CATALYTIC EFFECTS
PROPYLENE
ALUMINIUM OXIDES
ANTIMONY OXIDES
CATALYSTS
CATALYTIC CONVERTERS
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
MOLYBDENUM OXIDES
PHOSPHORUS OXIDES
REMOVAL
SURFACE AREA
TEMPERATURE EFFECTS
TITANIUM OXIDES
ALKENES
ALUMINIUM COMPOUNDS
ANTIMONY COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
EQUIPMENT
HYDROCARBONS
IRON COMPOUNDS
KINETICS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
POLLUTION CONTROL EQUIPMENT
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
SURFACE PROPERTIES
TESTING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
330702 - Emission Control- Carbon Monoxide
330704 - Emission Control- Hydrocarbons
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)