Activities of supported copper oxide catalysts in the NO+CO reaction at low temperatures

Hu, Yingfei; Dong, Lin; Wang, Jun; Ding, Weiping; Chen, Yi

doi:10.1016/s1381-1169(00)00299-5

Cited by 91 publications

(41 citation statements)

References 23 publications

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“…In the literature [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], copper oxide supported on different oxides (e.g., SiO 2 , TiO 2 , Al 2 O 3 , CeO 2 ) has been tested in the reaction of NO + CO. Among these supports, CeO 2 has received special attention due to the role of the oxygen buffering center through the facile Ce 4+ /Ce 3+ redox cycle [1,25].…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, the weak sintering resistance ability of CeO 2 can be compensated by the incorporation of Zr; in addition, CeO 2 redox capacity also can be enhanced. Dong and his group have reported the use of copper-based catalysts for the reaction of NO + CO [12,13,[15][16][17][18][19][20][21][22][23][24]. They suggested that the excellent performance of NO reduction and CO oxidation was attributed to the strong interaction between copper and the unique redox behavior of CeO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

Yuan

et al. 2016

Catalysts

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Abstract:In this work, the activity of xCuO-Ce 0.9 Zr 0.1 O 2 catalysts for the reaction of NO + CO was investigated. Especially, in situ DRIFTS was applied to investigate the surface species under the adsorption of NO and/or CO and the reaction of NO and CO to understand the key intermediates species and reaction process of NO + CO. The results suggest that the copper oxide species are well dispersed on the surface of the catalysts, which can be easily reduced to form Cu + species. The Cu + species are proposed to be important activity species. The results of this work also suggest that N 2 O 2 2− is likely an intermediate species that plays an important role in NO reduction by CO. Thus, more Cu + and highly dispersed copper oxide species are expected to be beneficial for the reaction of CO + NO over the xCuO-Ce 0.9 Zr 0.1 O 2 catalysts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

Yuan

et al. 2016

Catalysts

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“…The synergistic effect of Cu and Ce has also been well documented in literature. 4,5 The surface layer of unsupported CuCo 2 O 4 shifts to the reduced state when exposed to NO+CO gas mixture. The specific surface area of the support along with strong metal interaction (in presence of Cu and Ce) plays an important role in attaining the high catalytic activity in NO+CO reaction.…”

Section: Methodsmentioning

confidence: 99%

“…[4][5][6] Sakurai et al tested catalytic activities of cupric oxide and alumina-supported copper oxides in NO reduction by CO.…”

mentioning

confidence: 99%

“…3 Among the transition metals studied, copper show a potential activity in the NO+CO reaction and have been extensively studied. [4][5][6] Sakurai et al tested catalytic activities of cupric oxide and alumina-supported copper oxides in NO reduction by CO. 7 Metal oxides such as Ce and Ni are commonly employed O 2 storage component, which are frequently added to the catalyst to enhance the catalytic active sites. These oxides improve the performance of the catalyst, further making it less sensitive to temporary variations in the air-fuel ratio by getting reversibly oxidized or reduced at typical operating temperatures.…”

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A Study of NO+CO Reaction over Various Supported Catalysts in the Presence of O₂and H₂O

2007

Bulletin of the Korean Chemical Society

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NO and CO are the main gases emitted into the atmosphere from both stationary and mobile combustion systems. These toxic gases represent major form of pollutants and contribute mainly to the formation of smog, acid rain and ozone depletion in the stratosphere. The simultaneous elimination of these two toxic gases leading to non-toxic compounds such as N 2 and CO 2 is considered an efficient process. Although the studied reaction is spontaneous, it is well known that the presence of a catalyst is necessary. For the catalytic reduction of NO x , reducing agents such as carbon monoxide (CO), hydrogen (H 2 ), ammonia (NH 3 ), urea ((NH 2 ) 2 CO) and different hydrocarbons are usually being employed.1,2 Many supports such as alumina, titania, zirconia, ceria were usually used for dispersing the active phase for the elimination of nitrogen oxide. It is well known that supports play an important role in determining the nature and number of active sites, and consequently in the activity of the catalysts. The metal oxides are advantageous for the stability of the catalyst support and/or for enhancement of the catalyst activity under dynamic operations. 3Among the transition metals studied, copper show a potential activity in the NO+CO reaction and have been extensively studied. [4][5][6] Sakurai et al. tested catalytic activities of cupric oxide and alumina-supported copper oxides in NO reduction by CO.7 Metal oxides such as Ce and Ni are commonly employed O 2 storage component, which are frequently added to the catalyst to enhance the catalytic active sites. These oxides improve the performance of the catalyst, further making it less sensitive to temporary variations in the air-fuel ratio by getting reversibly oxidized or reduced at typical operating temperatures. Loof et al. stated that at higher temperatures, the O 2 storage capacity in catalysts containing Pt, Rh, Ni and Ce supported on Al 2 O 3 , Ni is found to be the dominant storage metal and Ce predominates over Pt and Rh. 8 The reduced surface of Ce in contact with reduced noble metals is the most effective state of the catalyst and greater activity is detected with decreasing CeO 2 crystallite size.9 Addition of cerium oxide play an important role in providing oxygen storage by transforming between Ce 2 O 3 under reducing conditions and CeO 2 under oxidizing conditions. 10 It is further believed that doped ceria inhibits the deactivation of active components in the reaction due to the sintering of the metals and surface deterioration of the support. Garcia et al. pointed out that the Cu-Ce interaction affected the reactivity of the catalysts towards NO thereby increasing the amount of adsorbed species which in turn lead to high NO adsorption at low temperature.11 The NO dissociation peaks were shifted towards low temperature upon addition of ZrO 2 onto CuO/TiO 2 , indicating NO decomposition activity was higher in CuO-ZrO 2 / TiO 2 than by CuO/TiO 2 .12 Hernandez et al. suggested that the presence of acid-base sites on Pt/ZrO 2 -CeO 2 seemed to be important for...

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Operando UV/Vis Analysis of the Synergy Effect between Copper and Gold in Nitric Oxide Reduction over Gold and Copper on Alumina Catalysts

et al. 2015

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Mono‐ (Cu or Au) and bi‐metallic AuCu nanoparticles were prepared by a modified polyol reduction method and deposited onto Al2O3 followed by calcination at 500 °C in air. The synthesised catalysts were tested for their activity for NO reduction with CO in excess H2O between 50 and 500 °C at a contact time relevant for automotive convertors. The bi‐metallic catalysts showed a significantly higher activity than Cu/Al2O3 and Au/Al2O3, and the latter was inert for the target reaction. In addition, the activity depended greatly on the Au/Cu ratio, which thus demonstrates a synergy effect between these two metals. Operando UV/Vis spectroscopy provided direct evidence for the transformation of initially oxidised CuOx species into metallic Cu0, which is the only active species for NO reduction. Promotion with Au was found to accelerate the reduction of Cu2+/Cu+ to Cu0.

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Activities of supported copper oxide catalysts in the NO+CO reaction at low temperatures

Cited by 91 publications

References 23 publications

Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

A Study of NO+CO Reaction over Various Supported Catalysts in the Presence of O₂and H₂O

Operando UV/Vis Analysis of the Synergy Effect between Copper and Gold in Nitric Oxide Reduction over Gold and Copper on Alumina Catalysts

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Activities of supported copper oxide catalysts in the NO+CO reaction at low temperatures

Cited by 91 publications

References 23 publications

Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies

A Study of NO+CO Reaction over Various Supported Catalysts in the Presence of O2and H2O

Operando UV/Vis Analysis of the Synergy Effect between Copper and Gold in Nitric Oxide Reduction over Gold and Copper on Alumina Catalysts

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A Study of NO+CO Reaction over Various Supported Catalysts in the Presence of O₂and H₂O