Studies on Cu/CeO2: A New NO Reduction Catalyst

Bera, Parthasarathi; Aruna, S.T.; Patil, K. C.; Hegde, M. S.

doi:10.1006/jcat.1999.2532

Cited by 158 publications

(99 citation statements)

References 36 publications

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“…10 profile consisted of a low-temp main peak at 85°C and a second -lower in intensity-peak at 250°C. It has also to be noted that the amount of adsorbed CO 2 for CuOCeO 2 catalysts seems to have quite similar values with those for pure CuO and pure CeO 2 , implying that CO 2 adsorption on CuO-CeO 2 catalysts takes place on both CuO and CeO 2 .…”

Section: Resultsmentioning

confidence: 99%

“…The beneficial catalytic properties of ceria are well represented in Cu-Ce oxide catalysts, which have been successfully tested in many catalytic reactions [3][4][5][6][7][8][9][10][11][12][13]. Liu and Flytzani-Stephanopoulos were the first to report that the Cu-Ce-O system is very active for complete oxidation of CO [3] with catalytic activity comparable or even superior to that of Pt-based catalysts.…”

Section: Introductionmentioning

confidence: 98%

“…The redox properties of ceria can enhance the catalytic performance of copper oxide in CO oxidation reaction, since additional active sites, generated from oxygen vacancies, are present at the interface of the two phases [3,7]. Concerning the nature of the active copper species, it is generally accepted that these are related to well-dispersed states of copper, probably in the form of copper oxide clusters in contact with the ceria and/or as an interfacial solid solution [3,[6][7][8][9][10][13][14][15][16][17][18][19][20][21][22][23]. The correlation between the reducibility of highly dispersed copper oxide species and their catalytic activity appears to be well established [3,5,7,8,13,16,[24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

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Adsorption and reaction of CO on CuO–CeO2 catalysts prepared by the combustion method

Avgouropoulos

Ioannides

2007

Catal Lett

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Temperature-programmed techniques were employed to investigate the interaction of CO with CuO-CeO 2 prepared by the urea-nitrates combustion method. These catalysts exhibited high and stable CO oxidation activity at relatively low reaction temperatures (< 150°C). The CO adsorption capacity and catalytic activity of the catalysts was analogous to the concentration of easily-reduced copper oxide surface species. TPD and TPSR results can be explained by a dual scheme of CO adsorption: (i) on oxidized sites, which get reduced with simultaneous formation of surface CO 2 and (ii) on reduced sites created by the former interaction. 10-20% of adsorbed CO desorbs molecularly in the absence of gas-phase O 2 , but reacts totally towards CO 2 in the presence of gas-phase O 2 . Inhibition by CO 2 observed under steady-state CO oxidation conditions is due to CO 2 adsorption as found by CO 2 -TPD.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Adsorption and reaction of CO on CuO–CeO2 catalysts prepared by the combustion method

Avgouropoulos

Ioannides

2007

Catal Lett

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“…Furthermore, the diffraction peaks appear to become weaker or even disappear with increasing Cu content, which indicates that the ordered mesoporous structure decreases to some extent. small clusters on the ceria surface, which cannot be detected using XRD; 54,55 2) the incorporation of CuO into the CeO 2 lattice, or a combination of these two phenomena. 56,57 The lattice parameters of the CeO 2 unit cell were obtained from the position of the (111) diffraction peak and are listed in Table 1.…”

Section: Template Removal and Preparation Of 3d Mesoporous Cuo X -Ceomentioning

confidence: 99%

Facile preparation of 3D ordered mesoporous CuOx–CeO2 with notably enhanced efficiency for the low temperature oxidation of heteroatom-containing volatile organic compounds

Chen

et al. 2013

RSC Adv.

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SBA-16 silica with intact surface hydroxyl groups was quickly obtained (5 min) via a fast-microwaveassisted method, and further adopted as an efficient template for the synthesis of three-dimensional (3D) ordered mesoporous CuO x -CeO 2 catalysts (htpCCx) through a simple and reproducible host-guest interaction. XRD, XPS, H 2 -TPR, and Raman results reveal that many of the Cu 2+ ions in htpCCx are incorporated into the CeO 2 lattice, leading to the formation of a Cu x Ce 12x O 22d solid solution, which produces a large number of oxygen vacancies and enhances the reducibility of the metal. The interaction of Cu and Ce is essential to the reaction as it maintains the Cu 2+ /Cu 1+ and Ce 4+ /Ce 3+ redox couples. The catalyst has a 3D mesostructure and possesses remarkably enhanced low-temperature activity for the combustion of epichlorohydrin. HtpCC20 has been identified as the most powerful catalyst for this reaction, with the reaction rate at 165 uC being about 6.3 and 33.3 times higher than those of catalysts synthesized using conventional incipient impregnation and thermal combustion methods, respectively. Furthermore, htpCC20 shows superior CO 2 selectivity (.99%) and stability (no deactivation occurs after 50 h reaction). It is believed that the dispersion of the active phase, density of surface active oxygen, and lowtemperature reducibility are the dominant factors governing the catalytic performance.

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“…With the exception of 6, the mixed oxides have a smaller crystallite size than plain ceria. [13,14] Possibly, the added metal influences the crystallite growth or the sintering behavior. [15] The lattice parameter of CeO 2 7 is in good agreement with the accepted value of 5.411 .…”

Section: Catalyst Preparation and Characterizationmentioning

confidence: 99%

Redox Kinetics of Ceria‐Based Mixed Oxides in Selective Hydrogen Combustion

et al. 2007

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Ceria-based mixed oxides, in which about 10 mol % of the cerium is replaced by another metal, catalyze the selective combustion of hydrogen from a mixture of hydrogen, propane, and propene at 550 degrees C. This makes them attractive catalysts for the oxidative dehydrogenation of propane. Hydrogen combustion shifts the equilibrium to the products side, supplies energy for the endothermic dehydrogenation, and simplifies product separation. The type of metal added has an important effect on the catalytic properties. To gain insight into the process, a set consisting of six mixed oxides was synthesized and the catalytic properties and redox behavior were tested. The mixed oxides generally release more oxygen than plain ceria. Mixed oxides containing Bi, Cu, Fe, Pd or Ca release between 1.6 and 2.0 mg of oxygen per 100 mg sample (compared to only 1.2 mg for plain ceria). This result is important for reactions in which the catalyst acts as an oxygen reservoir, such as selective hydrogen combustion. The temperature at which oxygen is released is generally lower for the mixed oxides, and varies from 110 degrees C (for Cu-CeO2) to 550 degrees C (for Ca-CeO2), which enables catalytic applications over a wide temperature range. The reduction rate at 550 degrees C is related to the reduction onset of the catalysts. Those catalysts with a relatively low reduction temperature, such as Cu-, Mn-, Bi-, and Pb-CeO2, show a high reduction rate, whereas those with a high reduction temperature, such as Ca-CeO2, Fe-CeO2, and plain ceria, reduce at a slower rate. The latter catalysts also have a low selectivity towards hydrogen combustion. The influence of the catalyst composition and crystallite size on the activity and selectivity is discussed.

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Studies on Cu/CeO2: A New NO Reduction Catalyst

Cited by 158 publications

References 36 publications

Adsorption and reaction of CO on CuO–CeO2 catalysts prepared by the combustion method

Adsorption and reaction of CO on CuO–CeO2 catalysts prepared by the combustion method

Facile preparation of 3D ordered mesoporous CuOx–CeO2 with notably enhanced efficiency for the low temperature oxidation of heteroatom-containing volatile organic compounds

Redox Kinetics of Ceria‐Based Mixed Oxides in Selective Hydrogen Combustion

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