Update on the Science and Technology of Diesel Particulate                    Filters

Konstandopoulos, Athanasios G.; Papaioannou, Eleni

doi:10.14356/kona.2008007

Cited by 48 publications

(18 citation statements)

References 57 publications

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“…TEM studies by Gardini et al [15] on Ag/soot mixtures have indicated that tight contact corresponds to an extensive interface between primary particles of catalyst and soot, whereas loose contact corresponds to fewer contact points at the interface between coagulates of catalyst particles and coagulates of soot particles. In several experiments [11,[16][17][18][19][20] with oxidation of soot particles filtered from gas streams by a catalytic filter part of the soot oxidation has been observed to peak at a relatively low temperature in the range characteristic of tight contact with the catalyst, while another part of the soot oxidation has been observed to peak at a higher temperature more characteristic of loose contact with the catalyst. Hence an understanding of both tight and loose contact oxidation may be relevant for real filter applications.…”

Section: Introductionmentioning

confidence: 99%

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Christensen

Grunwaldt

Jensen

2016

Applied Catalysis B: Environmental

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The oxygen bond strength on a catalyst, as measured by the heat of oxygen chemisorption, is observed to be a very important parameter for the activity of the catalyst in soot oxidation. With both intimate contact between soot and catalyst (tight contact) and with the solids stirred loosely together (loose contact) the rate constants for a number of catalytic materials outline a volcano curve when plotted against their heats of oxygen chemisorption. However, the optima of the volcanoes correspond to different heats of chemisorption for the two contact situations. In both cases the activation energies for soot oxidation follow linear Brønsted-Evans-Polanyi relationships with the heat of oxygen chemisorption. Among the tested metal or metal oxide catalysts Co 3 O 4 and CeO 2 were nearest to the optimal bond strength in tight contact oxidation, while Cr 2 O 3 was nearest to the optimum in loose contact oxidation. The optimum of the volcano curve in loose contact is estimated to occur between the bond strengths of α-Fe 2 O 3 and α-Cr 2 O 3 . Guided by an interpolation principle Fe a Cr b O x binary oxides were tested, and the activity of these oxides was observed to pass through an optimum for an FeCr 2 O x binary oxide catalyst, which exhibited a rate constant at 550 °C that was 2.3 times higher than the one for pure α-Cr 2 O 3 and 29 times higher than the one for pure α-Fe 2 O 3 .

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Section: Introductionmentioning

confidence: 99%

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Christensen

Grunwaldt

Jensen

2016

Applied Catalysis B: Environmental

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“…In tests where soot and catalyst are crushed together (so-called tight contact), the oxidation occurs at a significantly lower temperature, compared to when soot and catalyst are stirred together with a spatula (so-called loose contact) [11]. Several experiments with diesel soot filters [10,[12][13][14][15] have indicated the presence of both contact types. An explanation of this may come from the environmental scanning electron microscopy experiments by Kameya and Lee [16], who observed that the catalytic oxidation at the interface between the bottom of the soot cake and the catalyst containing filter caused the soot cake to crack, leading to a delamination and subsequent diminishment or even loss of soot/catalyst contact [16].…”

Section: Introductionmentioning

confidence: 99%

Visualizing the mobility of silver during catalytic soot oxidation

Gardini

Christensen

Damsgaard

et al. 2016

Applied Catalysis B: Environmental

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The catalytic activity and mobility of silver nanoparticles used as catalysts in temperature programmed oxidation of soot:silver (1:5 wt:wt) mixtures have been investigated by means of flow reactor experiments and in situ environmental transmission electron microscopy (ETEM). The carbon oxidation temperature was significantly lower compared to uncatalyzed soot oxidation with soot and silver loosely stirred together (loose contact) and lowered further with the two components crushed together (tight contact). The in situ TEM investigations revealed that the silver particles exhibited significant mobility during the soot oxidation, and this mobility, which increases the soot/catalyst contact, is expected to be an important factor for the lower oxidation temperature. In the intimate tight contact mixture the initial dispersion of the silver particles is greater, and the onset of mobility occurs at a lower temperature which is consistent with the lower oxidation temperature of the tight contact mixture.

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“…Therefore, with increasingly stringent emission standards, the need for improved emission control systems for PM has become evident. Catalyst coated diesel particulate filter (DPF) is an efficient device to trap and simultaneously burn the soot within the exhaust temperature range (150-450 o C) [9]. The soot formula can be approximately given as C 8 H [10] which on combustion releases non-toxic gases found in the atmosphere.…”

Section: Canadian Chemical Transactionsmentioning

confidence: 99%

Effect of Preparation Method and Calcination Temperature on LaCoO3 Perovskite Catalyst for Diesel Soot Oxidation

Mishra¹,

Прасад

2015

Can Chem Trans

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Abstract:The present work attempts to scan the effect of preparation methods (co-precipitation, sol-gel and solution combustion synthesis) and calcination temperature (600-800 o C) on the efficiency of LaCoO 3 catalysts for soot oxidation. All the catalysts were highly selective towards CO 2 as no CO was detected in the flue gas. Catalyst produced following co-precipitation method revealed total soot oxidation at the lowest temperature (T f = 370 o C) than other two catalysts prepared by sol-gel (T f = 420 o C) and solution combustion synthesis (T f = 456 o C) methods. Irrespective of the preparation methods, 750 o C was the optimum calcination temperature of the precursors resulting LaCoO 3 catalysts which exhibited maximum activity for soot oxidation. In addition, the results showed that the specific surface areas of the catalysts decreased with increasing calcination temperature beyond 750 o C and consequently decreasing the activity of the catalyst.

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Update on the Science and Technology of Diesel Particulate Filters

Abstract: As diesel emission regulations become more stringent, diesel particulate filters (DPFs)

Cited by 48 publications

References 57 publications

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Visualizing the mobility of silver during catalytic soot oxidation

Effect of Preparation Method and Calcination Temperature on LaCoO3 Perovskite Catalyst for Diesel Soot Oxidation

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