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Flouty, Roula; Abi‐Aad, Edmond; Siffert, Stéphane; Aboukaı̈s, Antoine

doi:10.1023/a:1025818127541

Cited by 37 publications

(41 citation statements)

References 23 publications

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“…According to the catalysts screening compiled in Figure 3, ceria-base catalysts are among the most effective for soot combustion, and this has promoted an intense research activity during the last years on different ceria-based catalysts for Diesel soot combustion like, among others, ceria doped with Zr [25,[35][36][37][38], Fe [36,39], La [21,36,38], Pr [21,36], Sm [21,36], Tb [36], Cu [40][41][42], Mn [40,43], and Mo [44] and different compounds supported on ceria such as K/Ceria [34,45], Co/Ceria [45][46][47][48][49], Ba,K/Ceria [50,51], Cu-V/Ceria [52], Ag/Ceria [53,54] or Cu/Ceria [55].…”

Section: -Why Ceria Catalysts For Soot Combustion?mentioning

confidence: 99%

Diesel soot combustion ceria catalysts

Bueno‐López

2014

Applied Catalysis B: Environmental

388

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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Section: -Why Ceria Catalysts For Soot Combustion?mentioning

confidence: 99%

Diesel soot combustion ceria catalysts

Bueno‐López

2014

Applied Catalysis B: Environmental

388

243

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“…This activity loss is due to reductive sulfatization of manganese and ceria causing a drop in oxygen mobility and NO oxidation activity as shown in [11,14]. However, the activity loss is much more moderate in the case of the potassium doped oxide (figure 6b).…”

Section: Resultsmentioning

confidence: 94%

“…However, these materials loose their oxidative properties rapidly when exposed to sulfur due to reductive sulfatization. Regeneration requires high temperatures and the catalytic activity is not or only partly recovered due to changes in the catalyst structure [11,13,14].…”

Section: Introductionmentioning

confidence: 99%

Influence of Potassium Doping on the Activity and the Sulfur Poisoning Resistance of Soot Oxidation Catalysts

2006

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Soot oxidation on potassium nitrate impregnated cerium oxide and manganese cerium mixed oxide was investigated using TG-FTIR. It was found, that potassium nitrate promotes the soot oxidation by enhancing the contact between the soot and the catalyst, as soot ignition temperature corresponds to the melting point of potassium nitrate for both the individual and the mixed oxide. Since potassium nitrate is easier sulfatized than cerium or manganese, the susceptibility of the catalyst to sulfur poisoning is considerably decreased.

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“…In order to overcome this problem, new diesel catalytic converters are comprised of bulk CeO 2 admixed with Al 2 O 3 which effectively reduce the formation and subsequent emission of SO 2À 4 compounds [5]. The CeO 2 forms stable cerium sulfate at temperatures below 785°C [6].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Different SO2/SO3 Catalytic Media on High-Temperature Corrosion Processes (Hot Corrosion, Fireside Corrosion, Sulfidation–Oxidation)

et al. 2015

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In many laboratory hot corrosion (HC) experiments and other experiments involving sulfur commercial catalytic converters are used to catalyze the SO 2 þ 1=2O 2 ! SO 3 reaction. The conversion rate of SO 2 to SO 3 highly depends on the catalyst used and thus the HC results, especially in low-temperature HC conditions, may vary significantly depending on the catalyst selected. Different elements present in the catalyst affect the SO 2 to SO 3 conversion and with it the degree of HC induced attack. Modern automotive catalysts have low activity for the oxidation of SO 2 to SO 3 . The conversion of SO 2 to SO 3 can be enhanced by modifications of the catalyst, e.g. by using a Pt-gauze or dip-coating the catalyst in a Fe 2 O 3 solution.

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Untitled

Cited by 37 publications

References 23 publications

Diesel soot combustion ceria catalysts

Diesel soot combustion ceria catalysts

Influence of Potassium Doping on the Activity and the Sulfur Poisoning Resistance of Soot Oxidation Catalysts

The Effect of Different SO2/SO3 Catalytic Media on High-Temperature Corrosion Processes (Hot Corrosion, Fireside Corrosion, Sulfidation–Oxidation)

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