Co3O4–CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

Dhakad, Manju; Mitshuhashi, T; Nagababu, Penumaka; Doggali, Pradeep; Bakardjiva, S; Šubrt, Ján; Fino, Debora; Haneda, Hajime; Labhsetwar, Nitin

doi:10.1016/j.cattod.2007.12.035

Cited by 81 publications

(46 citation statements)

References 21 publications

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“…The activation energies for the non-catalyzed and catalyzed reactions were 160 and 130141 kJ·mol ¹1 , respectively, and the presence of a catalyst did significantly influence this activation energy. The activation energy for the non-catalyzed one was consistent with that (163 kJ·mol ¹1 ) reported by Dhakad et al 18) Such a difference may be caused by the evolution of active oxygen from the catalyst. As seen in Table 2, the small changes observed in the activation energies for the catalyzed reaction are thought to be due to the difference in the specific surface areas.…”

Section: Carbon Oxidation Performance Evaluated Bysupporting

confidence: 90%

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La0.9Ag0.1FeOα synthesized at low temperature using co-precipitation method—

Nakayama

Tokunaga

Shiomi

et al. 2013

J. Ceram. Soc. Japan

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The perovskite oxide, LaFeO 3 , was synthesized by different preparation methods, i.e., the calcination of co-precipitated precursors [La(Ag)FeCO 3 and LaFeCO 3 ] and a mixture of La 2 O 3 and Fe 2 O 3 (LaFeO). By using the solution of Ag, the formation temperature (600°C) of the LaFeO 3 single phase obtained by the calcining of La(Ag)FeCO 3 was about 500°C lower than that of LaFeCO 3 . The formation temperature of the LaFeO 3 single phase of LaFeO was 1100°C as well as that of LaFeCO 3 . Their carbon oxidations were investigated by DSC (differential scanning calorimetry) measurements. The DSC exothermic peak of La 0.9 Ag 0.1 FeO ¡ obtained by the calcining of La(Ag)FeCO 3 at 700°C occurred at 409°C and showed a higher carbon oxidation activity when compared to LaFeO 3 (477 and 562°C) obtained by the calcining of LaFeCO 3 and LaFeO at 1100°C. The carbon oxidation activation energies observed for the non-catalyzed and catalyzed reactions (mixture of La 0.9 Ag 0.1 FeO ¡ ) were 160 and 130 kJ·mol ¹1 , respectively.

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Section: Carbon Oxidation Performance Evaluated Bysupporting

confidence: 90%

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La0.9Ag0.1FeOα synthesized at low temperature using co-precipitation method—

Nakayama

Tokunaga

Shiomi

et al. 2013

J. Ceram. Soc. Japan

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“…12,13 Recently growing scientific attention has been paid to Co 3 O 4 -based oxides as highly efficient catalysts for the complete abatement of unburned methane released from natural gas vehicles (NGVs). To this aim, different combinations of Co 3 O 4 and various oxide supports have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Pantaleo

Carlo

et al. 2015

Catal. Sci. Technol.

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aCrystalline cobalt oxides were prepared by a precipitation method using three different precipitation agents, ĲNH 4 ) 2 CO 3 , Na 2 CO 3 and COĲNH 2 ) 2 . Cobalt oxide nanoparticles corresponding to a Co 3 O 4 loading of 30 wt% were also deposited over high-surface area nanocrystalline ceria by the same precipitation agents. The effect of calcination temperature, 350 or 650°C, on the morphological and structural properties was evaluated. Characterization by BET, XRD, SEM, TEM, Raman spectroscopy, H 2 -TPR, XPS and NH 3 -TPD was performed and the catalytic properties were explored in the methane oxidation reaction. The nature of the precipitation agent strongly influenced the textural properties of Co 3 O 4 and the Co 3 O 4 -CeO 2 interface. The best control of the particle size was achieved by using COĲNH 2 ) 2 that produced small and regular crystallites of Co 3 O 4 homogeneously deposited over the CeO 2 surface. Such a Co 3 O 4 -CeO 2 system precipitated by urea showed enhanced low-temperature reducibility and high surface Co 3+ concentration, which were identified as the key factors for promoting methane oxidation at low temperature. Moreover, the synergic effect of cobalt oxide and nanocrystalline ceria produced stable full conversion of methane in the entire range of investigated temperature, up to 700-800°C, at which Co 3 O 4 deactivation usually occurs.

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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

395

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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Co3O4–CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

Cited by 81 publications

References 21 publications

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La<sub>0.9</sub>Ag<sub>0.1</sub>FeO<sub>α</sub> synthesized at low temperature using co-precipitation method—

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La<sub>0.9</sub>Ag<sub>0.1</sub>FeO<sub>α</sub> synthesized at low temperature using co-precipitation method—

Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Diesel soot combustion ceria catalysts

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Co3O4–CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

Cited by 81 publications

References 21 publications

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La<sub>0.9</sub>Ag<sub>0.1</sub>FeO<sub>α</sub> synthesized at low temperature using co-precipitation method—

Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La<sub>0.9</sub>Ag<sub>0.1</sub>FeO<sub>α</sub> synthesized at low temperature using co-precipitation method—

Co3O4 particles grown over nanocrystalline CeO2: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Diesel soot combustion ceria catalysts

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Co₃O₄ particles grown over nanocrystalline CeO₂: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation