Catalytic performances of ceria and ceria-zirconia materials for the combustion of diesel soot under NOx/O2 and O2. Importance of the cerium precursor salt

Guillén-Hurtado, Noelia; Bueno‐López, Agustín; Garcı́a-Garcı́a, Avelina

doi:10.1016/j.apcata.2012.06.028

Cited by 48 publications

(43 citation statements)

References 49 publications

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“…Thus, for example, ceria-zirconia is the least active sample at the beginning of the reaction, but its behaviour is progressively improved until becoming the second sample in the activity order (just after Cu 2%). A reasonable hypothesis to explain these results is the relevance of the active oxygen assisted-soot combustion (becoming prevalent at high temperatures) besides the NO 2 -assisted soot combustion, which is important to initiate the soot combustion process, as previously reported by the authors [2,56]. It is interesting to remind that the BET surface areas decrease progressively as the copper loading increases on the samples (from 96 to 57 m 2 /g) and this fact diminishes the active oxygen transfer to the soot surface as the point of contacts among the soot surface and the catalyst particles play a key role under the loose contact mode.…”

Section: Catalytic Soot Combustionmentioning

confidence: 62%

“…The choice of the particular formulation Ce 0.8 Zr 0.2 O 2 for the support has been done according to our previous optimisation studies [2].…”

Section: Page 3 Of 38mentioning

confidence: 99%

“…Zirconium doping confers thermal stability to ceria as well. The importance of these mixed oxides as catalysts has raised several studies for application to different oxidation reactions [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Preparation, characterisation and testing of CuO/Ce0.8Zr0.2O2 catalysts for NO oxidation to NO2 and mild temperature diesel soot combustion

Giménez-Mañogil

Bueno‐López

Garcı́a-Garcı́a

2014

Applied Catalysis B: Environmental

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Please cite this article as: J. Giménez-Mañogil, A. Bueno-López, A. García-García, Preparation, characterisation and testing of CuO/Ce 0.8 Zr 0.2 O 2 catalysts for NO oxidation to NO 2 and mild temperature diesel soot combustion., Applied Catalysis B, Environmental (2014), http://dx.doi.org/10. 1016/j.apcatb.2014.01.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCuO/ceria-zirconia catalysts have been prepared, deeply characterised (N 2 adsorption-desorption isotherms at -196°C, XRD, Raman spectroscopy, XPS, TEM and H 2 -TPR) and tested for NO oxidation to NO 2 in TPR conditions, and for soot combustion at mild temperature (400ºC) in a NOx/O 2 stream. The behaviour has been compared to that of a reference Pt/alumina commercial catalyst. The ceria-zirconia support was prepared by the co-precipitation method, and different amounts of copper (0.5, 1, 2, 4 and 6 wt%) were loaded by incipient wetness impregnation.The results revealed that copper is well-dispersed onto the ceria-zirconia support for the catalysts with low copper loading and CuO particles were only identified by XRD in samples with 4 and 6% of copper. A very low loading of copper increases significantly the activity for the NO oxidation to NO 2 with regard to the ceria-zirconia support and an optimum was found for a 4%CuO/ceria-zirconia composition, showing a very high activity (54% at 348ºC). The soot combustion rate at 400ºC obtained with the 2%CuO/ceria-zirconia catalyst is slightly lower to that of 1%Pt/alumina in terms of mass of catalyst but higher in terms of price of catalyst.

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Section: Catalytic Soot Combustionmentioning

confidence: 62%

“…The choice of the particular formulation Ce 0.8 Zr 0.2 O 2 for the support has been done according to our previous optimisation studies [2].…”

Section: Page 3 Of 38mentioning

confidence: 99%

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Preparation, characterisation and testing of CuO/Ce0.8Zr0.2O2 catalysts for NO oxidation to NO2 and mild temperature diesel soot combustion

Giménez-Mañogil

Bueno‐López

Garcı́a-Garcı́a

2014

Applied Catalysis B: Environmental

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“…The redox properties of the Ce 3+/4+ couple and the capacity of cerium oxide to exchange oxygen with the gas phase are also behind the good catalytic performance of ceria-based materials as soot combustion catalysts, as it is discussed in the coming sections. catalysts, including pure oxides [10,11], platinum [12,13], copper [14][15][16][17][18][19], zinc [16] and cobalt [12] catalysts, perovskites [14,15,17,19], spinels [13,16], manganese catalysts with birnessite and cryptomelane structure [10,20], alkali [14,17] and alkali earth metals-containing catalysts [15,17,19] and pure and doped cerium oxides [21][22][23][24][25][26][27][28][29][30][31]. The catalysts whose results are included in Figure 3 are the most active that have been prepared of a particular composition.…”

Section: -Why Ceria Catalysts For Soot Combustion?mentioning

confidence: 99%

Diesel soot combustion ceria catalysts

Bueno‐López

2014

Applied Catalysis B: Environmental

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243

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This review article summarizes the contents of the keynote lecture with the same tittle presented at the 7 th edition of the International Conference on Environmental Catalysis hold in Lyon (France) in September 2012. Different aspects of the ceria-catalyzed Diesel soot combustion reactions have been critically discussed, such as the high catalytic activity of ceria for Diesel soot combustion in comparison to some other potential catalysts, the potential ceria-catalyzed Diesel soot combustion mechanisms (the so-called NO 2 -assisted mechanism and the active oxygen mechanism) and the effect of ceria doping with suitable cations like those of Pr, La or Zr. Ceria must be doped in order to enhance thermal stability, but ceria doping also changes different physicochemical and catalytic properties of ceria. Zr-doping, for instance, has a double role on ceria as soot combustion catalyst: enhances ceria oxidation capacity of the adsorbed NOx species (positive effect) but stabilizes NO 2 on surface (negative effect). The surface properties of a ceria catalyst are usually more important than those of bulk: high surface area/small crystal size usually has a positive effect on the catalyst performance and, in mixed oxides, the surface composition also plays a role. The optimal dopant loading depends on the foreign cation being, for instance, around 5-10%, 20-30% and 50 mole % for La 3+ , Zr 4+ , and Pr 3+ / 4+ , respectively.Keywords: DPF regeneration; soot; ceria; doped-ceria; Diesel engine contamination. 2This review article summarizes the contents of the keynote lecture with the same tittle presented at the 7 th edition of the International Conference on Environmental Catalysis hold in Lyon (France) in September 2012. 1.-The problem.Soot particles are formed as undesired by-products in combustion process, being one of the main pollutants emitted by Diesel engines together with NOx, CO and unburned hydrocarbons [1]. Typical gas exhaust composition of a Diesel car, which is summarized in Table 1, is 30-80 ppm hydrocarbons, 200-1500 ppm CO, 300-1650 ppm NO (~ 0 ppm NO 2 ), 5-18% O 2 , > 2% H 2 O and > 2% CO 2 .Soot particles consist of a carbon nucleus with some inorganic material and adsorbed hydrocarbons, SO x , and water [2]. Figure 1 shows TEM images of a real soot sample. The single particles of few nanometers present an amorphous core surrounded by a graphitic shell, and such single particles agglomerate in larger entities with size typically in the range 0.1-10 µm [3].Several adverse effects on health have been attributed to soot. A fraction of these particles (the so-called PM-10, with size smaller than 10 m) can penetrate the respiratory tract and are deposited on lungs increasing cancer risk, asthma and bronchitis. The adsorbed hydrocarbons are mutagenic substances and SO x in contact with water form strong acid compounds.Diesel particle traps with different designs can be used for soot removal from gas streams, wall-flow monoliths being the most popular [3,4]. Figure 2 shows a commercial SiC Diesel Part...

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“…For example, the SCR reaction rate substantially increased when a fraction of NO in the exhaust is converted to NO 2 [1]. The oxidized NO 2 can also assist the oxidation of soot [2]. So it is important to oxidize NO-NO 2 and NO oxidation received increasing attention by many research groups [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Influence of the preparation method on the catalytic activity of Co/Zr1−xCexO2 for NO oxidation

Shang

Zhong

Cai

2015

Journal of Molecular Catalysis A: Chemical

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Catalytic performances of ceria and ceria-zirconia materials for the combustion of diesel soot under NOx/O2 and O2. Importance of the cerium precursor salt

Cited by 48 publications

References 49 publications

Preparation, characterisation and testing of CuO/Ce0.8Zr0.2O2 catalysts for NO oxidation to NO2 and mild temperature diesel soot combustion

Preparation, characterisation and testing of CuO/Ce0.8Zr0.2O2 catalysts for NO oxidation to NO2 and mild temperature diesel soot combustion

Diesel soot combustion ceria catalysts

Influence of the preparation method on the catalytic activity of Co/Zr1−xCexO2 for NO oxidation

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