Reduction of nitrogen oxides by carbon monoxide over an iron oxide catalyst under dynamic conditions

Redn. of NO and N2O by CO over a SiO2-supported iron oxide catalyst was studied by the transient response method, with different initial oxidn. states of the catalyst, i.e., completely reduced (Fe3O4), or oxidized (Fe2O3). The affect of CO pre-adsorption was also studied. From the material balance on the gas-phase species, it was shown that the compn. of the catalyst changes during relaxation to steady-state. The degree of redn. of the catalyst at steady-state could thus be estd. During the transient period, CO was shown to inhibit N2O as well as NO redns. by adsorption on reduced sites. Activity of the reduced catalyst was substantially higher as compared to the oxidized catalyst for both reactions. On this basis, it was attempted to keep the catalyst in a reduced state by periodically reducing it with CO. As a result, a significant increase in reactor performance with respect to steady-state operation could be achieved for N2O redn. by CO. Finally, the dynamic behavior of the N2O-CO and NO-CO reactions made it possible to evidence reaction steps, the occurrence of which could not be shown during previous investigations on the sep. interactions of the reactants with the catalyst. [on SciFinder (R)]


Published in:
Applied Catalysis B: Environmental, 17, 4, 357-369
Year:
1998
Keywords:
Note:
CAN 129:234816
59-4
Air Pollution and Industrial Hygiene
Institute of Chemical Engineering,Federal Institute of Technology,Lausanne,Switz.
Journal
0926-3373
written in English.
7631-86-9 (Silica) Role: CAT (Catalyst use), USES (Uses) (iron oxide supported by; nitrogen oxide redn. by carbon monoxide over reduced and oxidized iron oxide catalyst under dynamic conditions); 124-38-9 (Carbon dioxide); 7727-37-9 (Nitrogen) Role: FMU (Formation, unclassified), PEP (Physical, engineering or chemical process), FORM (Formation, nonpreparative), PROC (Process) (nitrogen oxide redn. by carbon monoxide over reduced and oxidized iron oxide catalyst under dynamic conditions); 10024-97-2 (Nitrous oxide); 10102-43-9 (Nitric oxide) Role: PEP (Physical, engineering or chemical process), POL (Pollutant), REM (Removal or disposal), OCCU (Occurrence), PROC (Process) (nitrogen oxide redn. by carbon monoxide over reduced and oxidized iron oxide catalyst under dynamic conditions); 630-08-0 (Carbon monoxide) Role: RCT (Reactant), RACT (Reactant or reagent) (nitrogen oxide redn. by carbon monoxide over reduced and oxidized iron oxide catalyst under dynamic conditions); 1309-37-1 (Iron oxide); 1317-61-9 (Iron oxide) Role: CAT (Catalyst use), USES (Uses) (silica-supported; nitrogen oxide redn. by carbon monoxide over reduced and oxidized iron oxide catalyst under dynamic conditions)
Laboratories:




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