DPF Supporting Nano-Structured Perovskite Catalysts for NOx and Diesel Soot Emission Control in Commercial Vehicles

Renzullo, A.; Tarabocchia, A.; Villata, Giorgio; Mescia, Davide; Caroca, Jose Carlos; Raimondi, Andrea; Russo, Nunzio; Fino, Debora; Saracco, Guido; Specchia, Vito

doi:10.4271/2007-01-4173

Cited by 3 publications

(3 citation statements)

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“…Many studies have shown that if a zeolite-based SCR catalyst can oxidize NO to NO 2 in situ, then its low-temperature SCR activity will be significantly enhanced because the presence of NO 2 allows the “fast SCR” reaction to proceed. , In addition, if a DOC catalyst is active in NO oxidation to NO 2 , this can lead to a decrease in the temperature required for soot oxidation on a DPF. ,,,, NO oxidation conversion as a function of temperature over oxidized ceria results is shown in Figure . NO oxidation was observed above 200 °C, increased with temperature to ∼400 °C, and then decreased with increasing temperature due to thermodynamic equilibrium limitations.…”

Section: Results and Discussionmentioning

confidence: 99%

“…21,22 In addition, if a DOC catalyst is active in NO oxidation to NO 2 , this can lead to a decrease in the temperature required for soot oxidation on a DPF. 12,19,20,32,33 NO oxidation conversion as a function of temperature over oxidized ceria results is shown in Figure 4. NO oxidation was observed above 200 °C, increased with temperature to ∼400 °C, and then decreased with increasing temperature due to thermodynamic equilibrium limitations.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…Typically, the DOC is positioned upstream of the other catalysts to oxidize the CO and unburned hydrocarbon emissions and to oxidize NO to NO 2 . Engine out ratios of NO 2 /NO are typically low, and a higher ratio of NO 2 /NO increases the low-temperature NO x conversion efficiency of SCR and NSR catalysts and NO 2 can oxidize soot at lower temperatures than O 2 . − In terms of DPFs, recently it has been reported that ceria as a support results in interesting properties for soot combustion catalysts due to a high availability of surface oxygen and good surface redox properties. ,,− …”

Section: Introductionmentioning

confidence: 99%

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Characterization of Ceria’s Interaction with NO_x and NH₃

et al. 2013

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Ceria is a common component of engine aftertreatment catalysts due to its oxygen storage ability, its redox properties, and its role in stabilizing Pt against sintering. The interactions between ceria and NH3 or NO x were investigated to better understand the role of ceria in oxidation reactions occurring over a diesel oxidation catalyst, in the reduction of NO x on lean NO x traps, and in the selective catalytic oxidation (SCO) of NH3. Ceria proved active in NO oxidation, selective catalytic reduction of NO by NH3 (NH3–SCR), and NH3–SCO reactions. Between 100 and 450 °C, both NH3 and NO x adsorbed on ceria simultaneously. In the absence of NO x , NH3 was oxidized over CeO2 forming N2 via a two-step selective catalytic reduction mechanism at low temperature and NO x at high temperature. In the presence of NO x , NH3 reacted with adsorbed NO x species, again forming N2 at lower temperatures (250–450 °C), while at higher temperature, a significant portion of the NH3 was oxidized, with product NO formed.

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