Kinetics of the CO oxidation by O2 and N2O over Cu‐Cr/Al2O3

Dekker, N.J.J.; Hoorn, Johan F.; Stegenga, S.; Kapteijn, Freek; Moulijn, Jacob A.

doi:10.1002/aic.690380307

Cited by 32 publications

(18 citation statements)

References 48 publications

(74 reference statements)

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“…The total amount of carbonate and carbonyl groups must be the same in both cases, indicating that NO has converted only part of the carbonate species. In other words, 2%NO/He does not oxidize the catalyst as good as 2.5%O 2 /He, which agrees with results showing that reduction of NO in a NO + CO + O 2 mixture only occurs when all O 2 is consumed (2,9,10).…”

Section: Series (I)supporting

confidence: 91%

“…A kinetic study indicated that the steady-state NO reduction by CO over Cu-Cr proceeds according to both reaction steps (9,10). The importance of the latter mechanism in the NO reduction over Rh was demonstrated in a kinetic analysis of Cho (22,23) which showed that reaction between N 2 O and CO leading to N 2 can be two or three orders of magnitude faster as an intermediate reaction in a NO + CO-containing gas phase than the isolated N 2 O + CO reaction.…”

Section: Overallmentioning

confidence: 99%

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NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

Dekker

Kraneveld

Bliek

et al. 1997

Journal of Catalysis

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Section: Series (I)supporting

confidence: 91%

Section: Overallmentioning

confidence: 99%

NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

Dekker

Kraneveld

Bliek

et al. 1997

Journal of Catalysis

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“…CO2 production does not start instantaneously after the step change; it is slightly delayed. Since oxygen is consumed directly after the step change this means that reoxidation is not the limiting stage in the CO oxidation over chromium, in agreement with a kinetic study over a Cu-Cr catalyst (Dekker et al, 1992;Kapteijn et al, 1993). The oxygen appears when the CO2 declines.…”

Section: Resultssupporting

confidence: 65%

Modelling the transient kinetics of heterogeneous catalysts. CO-oxidation over supported Cr and Cu

Dekker

Klopper

Bliek

et al. 1994

Chemical Engineering Science

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Modelling the transient kinetics of heterogeneous catalysts. CO oxidation over supported Cr and Cu Dekker, F.H.M.; Klopper, G.; Bliek, A.; Kapteijn, F.; Moulijn, J.A. Published in:Chemical Engineering Science Link to publicationCitation for published version (APA): Dekker, F. H. M., Klopper, G., Bliek, A., Kapteijn, F., & Moulijn, J. A. (1994). Modelling the transient kinetics of heterogeneous catalysts. CO oxidation over supported Cr and Cu. Chemical Engineering Science, 49(24), 4375-4390. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract--This article illustrates the capabilities of the step response method in the determination of the mechanism and kinetics of a heterogeneously catalyzed reaction. The step response method was applied to investigate the CO oxidation over alumina-supported chromium and copper. Detailed mechanisms of this reaction were determined by measuring the isothermal reduction and oxidation of the catalysts via switching the gas-phase composition from inert (He) to either reducing (CO) or oxidizing (02) conditions, Modelling the obtained response curves has given information on the reaction rate constants of the elementary steps in the CO oxidation over the Cr and Cu catalyst. Here, only a minimum number of reaction steps and parameters have been used, but they are still physically acceptable. The reduction of the Cr catalyst was found to proceed via reaction of adsorbed CO. The activation energy of this process is 95 kJ mol -~. The dispersion of the Cr catalyst is 20%, whereas only half the metal atoms at the catalyst surface participate in the oxidation and reduction. The latter metal atoms are coordinated to about four removable oxygen atoms Reduction of the Cu catalyst takes place in three steps: first oxygen on the surface is removed via reaction of CO from the gas phase. Next the oxygen in the surface is removed via reaction of adsorbed CO, and finally the oxygen from the bulk of the catalyst that has diffused to the surface is removed. The activation energy of all three processes has been determined. The dispersion of the Cu catalyst was found to be about 22%, MODELLING THE TRANSIENT KINETICS OF H E T E R O G E N E O U S CATALYSTS. CO-OXIDATION OVER I N T R O D U C T I O NIn heterogeneous catalysis much effort is put into est...

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“…These authors have studied also the effects of ZnO on solid-solid interactions taking place in CuO/Al 2 O 3 solids. Dekker et al (1992) have reported that CO oxidation by O 2 over copper-based catalyst is considered to proceed according to an oxidation-reduction mechanism of the active phase. Possible redox couples under working conditions are Cu + -Cu 2+ , Cu 0 -Cu 2+ and Cu 0 -Cu + .…”

Section: Introductionmentioning

confidence: 99%

Catalytic oxidation of CO by O₂ over nanosized CuO–ZnO system prepared under various conditions

et al. 2009

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A series of copper and zinc mixed oxides composed of equimolar ratio and treated with 0.05 Al 2 O 3 /mol catalyst has been prepared by coprecipitation method using their nitrates in presence of 1 M NaOH solution. The precipitation was carried out at a pH 9.5 and 50 • C. The results revealed that the bulk of various solids consisted of CuO and ZnO having ratios varying between 0.84 and 0.98. On the other hand, the values of surface concentrations of copper and zinc were bigger than those present in the bulk. The values of surface Cu/Zn ratio varied between 1.04 and 1.46 depending on the mode of preparation and calcination conditions. The mixed solids existed as nanocrystalline CuO and ZnO phases. The surface characteristics are strongly dependent on mode of coprecipitation and calcination temperature. The computed S BET values varied between 146 and 23 m 2 /g depending on mode of coprecipitation and calcination temperature. The increase of calcination temperature of different adsorbents within 300-400 • C led to a significant progressive decrease in the BET-surface area with subsequent increase in the values of mean pore radius. All adsorbents are mesoporous solids. All prepared solids showed a good catalytic activity in CO oxidation by O 2 , which proceeds via first order kinetics in all cases. The activation energy of the catalysed reaction was determined for various solids and the computed values were very small indicating the big catalytic activity of the investigated solids.On a préparé une série d'oxydes mixtes de cuivre et de zinc composés d'un rapportéquimolaire et traités avec un catalyseur de 0,05 Al 2 O 3 /mol par la méthode de la coprécipitation en utilisant leurs nitrates en présence de 1 M de solution de NaOH. La précipitation s'est effectuéeà un pH de 9,5 età une température de 50 • C. Les résultats ont révélé que la majeure partie de divers solides consistait en du CuO et du ZnO selon des rapports variant entre 0,84 et 0,98. D'un autre côté, les valeurs des concentrations superficielles de cuivre et de zincétaient supérieuresà celles présentes dans ce lot de solides. Les valeurs du rapport superficiel Cu/Zn variaient entre 1,04 et 1,46 selon le mode de préparation et les conditions de calcination. Les solides mixtes existaient sous forme de phases nanocrystallines du CuO et du ZnO. Les caractéristiques superficielles dépendent fortement du mode de coprécipitation et de la température de calcination. Les valeurs S BET calculées variaient entre 146 et 23 m 2 /g selon le mode de coprécipitation et la température de calcination. L'augmentation de la température de calcination de différents agents d'adsorption dans les limites de 300 et 400 • C a menéà une diminution progressive importante de l'aire superficielle BET, de même qu'une augmentation ultérieure des valeurs du rayon moyen des pores. Tous les agents d'adsorption sont des solides mésoporeux. Tous les solides préparés ont montré une bonne activité catalytique dans l'oxydation du CO par l'O 2 , qui suit une cinétique du premier ordre dans tous le...

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Kinetics of the CO oxidation by O₂ and N₂O over Cu‐Cr/Al₂O₃

Cited by 32 publications

References 48 publications

NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

Modelling the transient kinetics of heterogeneous catalysts. CO-oxidation over supported Cr and Cu

Catalytic oxidation of CO by O₂ over nanosized CuO–ZnO system prepared under various conditions

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Kinetics of the CO oxidation by O2 and N2O over Cu‐Cr/Al2O3

Cited by 32 publications

References 48 publications

NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

NO Reduction over Alumina-Supported Cu and Cu–Cr Studied with the Step–Response Method

Modelling the transient kinetics of heterogeneous catalysts. CO-oxidation over supported Cr and Cu

Catalytic oxidation of CO by O2 over nanosized CuO–ZnO system prepared under various conditions

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Kinetics of the CO oxidation by O₂ and N₂O over Cu‐Cr/Al₂O₃

Catalytic oxidation of CO by O₂ over nanosized CuO–ZnO system prepared under various conditions