The influence of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.gif" overflow="scroll"><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">SO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math> on the catalytic combustion of soot using O2 and NO/O2 mixtures over Na-promoted Al2O3 catalysts

Sullivan, James A.; Keane, Orla; Maguire, Linda

doi:10.1016/j.catcom.2005.04.008

Cited by 12 publications

(5 citation statements)

References 11 publications

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“…The NO+O 2 mixture has two roles in the soot removal mechanism, in agreement with other authors for DPF materials. , On one hand, it can react with soot as the gas–solid reaction that has been described above with activation energy values around 100 kJ mol –1 , which, for this material, was superimposed with other processes and cannot be adjusted. On the other hand, NO can be oxidized to NO 2 and adsorbed as nitrites or nitrates, , which lately react with soot being more reactive than gas-phase NO 2 . The profile of NO (Figure S2) also confirmed NO consumption at temperatures higher than 600 K to form nitrate species, which is the characteristic that makes this Pt–Ba–K/Al 2 O 3 an effective catalyst for NSR technology.…”

Section: Resultsmentioning

confidence: 99%

Understanding of Soot Removal Mechanism over DeNOx-Catalysts as Passive Converters

Cortés‐Reyes

Herrera

Larrubia

et al. 2021

Ind. Eng. Chem. Res.

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Although diesel particulate filters (DPFs) are able to efficiently remove soot and coupled NO x storage and reduction and selective catalytic reaction (NSR−SCR) technologies can considerably decrease NO x emissions, the elimination of soot over Pt−Ba− K/Al 2 O 3 and Cu-CHA NO x removal catalysts acting as passive converters is still an open topic. The estimation of the occurrence frequency and activation energy values from the distribution function of activation energy allowed the identification of sequential steps involved in the soot removal. For that, TG-MS nonisothermal experiments were carried out over the model of deNO x catalysts under a NO+O 2 atmosphere. For bare soot, only gas-phase components react with carbon particles to produce CO 2 at high temperatures with E a values higher than 120 kJ mol −1 for the direct oxidation by molecular oxygen and 114 kJ mol −1 for the assisted soot removal process by NO x . For the lean NO x trap (LNT) model catalyst, the combination of hydroxylated centers, provided by the incorporation of potassium responsible for the carbon elimination via gasification (70−90 kJ mol −1 ), and nitrate species stored onto the surface, involved in the elimination via oxidation (97 kJ mol −1 ), together with the gas-phase interaction, makes this catalyst an efficient soot passive converter. The Cu-SAPO-34 SCR catalyst with 4 wt % of copper located inside the framework and small pores of the chabazite structure are not able to act as a converter because soot removal takes place via assisted combustion with NO x and molecular oxygen, similar to the uncatalyzed process. CeO 2 , the main component of DPF, presented the lowest values of T 90 (923 K), ignition soot temperature, and activation energy due to the intervention of highly reactive oxygen species being the most effective soot converter in the low-temperature range.

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Section: Resultsmentioning

confidence: 99%

Understanding of Soot Removal Mechanism over DeNOx-Catalysts as Passive Converters

Cortés‐Reyes

Herrera

Larrubia

et al. 2021

Ind. Eng. Chem. Res.

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“…In the latter case NO, present in the exhaust gas (in combination with a suitable NO oxidation catalyst), promotes soot combustion through the formation of NO 2 which then reacts with C (s) transferring an O atom and regenerating NO [16][17] Since the oxidation of NO is a primary step both in the trapping onto an NSR material and the promotion of soot combustion on a DPF, the attempt to combine both of these technologies into a single catalytic bed seems obvious. Furthermore, it has been reported that the presence of a NSR system improves particulate removal from diesel exhausts [1,[18][19][20].…”

mentioning

confidence: 99%

The effect of C(s) on the trapping of NOx onto Pt/Ba/Al2O3 catalysts

Sullivan¹,

Dulgheru²

2010

Applied Catalysis B: Environmental

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“…The importance of the interaction between surface nitrates and soot and the beneficial effect on the soot oxidation process is also documented by Sullivan et al [98] suggesting that on the Na/Al 2 O 3 catalyst NO adsorbs in the form of nitrites/nitrates, which can further decompose, i.e., releasing NO 2 . Shuang et al [99] indicated the NO 2 derived from nitrates decomposition on Pt-Mg/Al 2 O 3 catalysts as beneficial for the soot oxidation activity.…”

Section: Dpnr Catalysts For the Simultaneous Removal Of No X And Sootmentioning

confidence: 68%

An Overview on the Catalytic Materials Proposed for the Simultaneous Removal of NOx and Soot

Castoldi

2020

Materials

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Vehicular pollution has become a major problem in urban areas due to the exponential increase in the number of automobiles. Typical exhaust emissions, which include nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), soot, and particulate matter (PM), doubtless have important negative effects on the environment and human health, including cardiovascular effects such as cardiac arrhythmias and heart attacks, and respiratory effects such as asthma attacks and bronchitis. The mitigation measures comprise either the use of clean alternative fuels or the use of innovative technologies. Several existing emission control technologies have proven effective at controlling emissions individually, such as selective catalytic reduction (SCR) and lean NOx trap (LNT) to reduce NOx and diesel particulate filter (DPF) specifically for PM abatement. These after-treatment devices are the most profitable means to reduce exhaust emissions to acceptable limits (EURO VI norms) with very little or no impact on the engine performances. Additionally, the relative lack of physical space in which to install emissions-control equipment is a key challenge for cars, especially those of small size. For this reason, to reduce both volume and cost of the after-treatment devices integrated catalytic systems (e.g., a sort of a “single brick”) have been proposed, reducing both NOx and PM simultaneously. This review will summarize the currently reported materials for the simultaneous removal of NOx and soot, with particular attention to their nature, properties, and performances.

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The influence of SO42- on the catalytic combustion of soot using O2 and NO/O2 mixtures over Na-promoted Al2O3 catalysts

Abstract: Publication information Catalysis Communications, 6 (7): 472-475Publisher Elsevier Item record/more information

Cited by 12 publications

References 11 publications

Understanding of Soot Removal Mechanism over DeNOx-Catalysts as Passive Converters

Understanding of Soot Removal Mechanism over DeNOx-Catalysts as Passive Converters

The effect of C(s) on the trapping of NOx onto Pt/Ba/Al2O3 catalysts

An Overview on the Catalytic Materials Proposed for the Simultaneous Removal of NOx and Soot

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