K-supported catalysts for diesel soot combustion: Making a balance between activity and stability

Li, Qian; Wang, Xiao; Chen, Hui; Xin, Ying; Tian, Guangkai; Lu, Chenxi; Zhang, Zhaoliang; Zheng, Lirong; Zheng, Lei

doi:10.1016/j.cattod.2015.07.036

Cited by 47 publications

(30 citation statements)

References 54 publications

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“…The significance of these results is in achieving the thermal conditions relevant for soot combustion in the temperature of real Diesel exhaust gases. The observed activity of the catalysts is comparable or better than found in literature [24,40,41]. In all tested conditions Pd/OL was the most active catalyst, achieving 50% soot conversion at 385, 450 and 541 °C for tight, loose + NO and loose contact conditions.…”

Section: Resultssupporting

confidence: 76%

Nanostructured Potassium-Manganese Oxides Decorated with Pd Nanoparticles as Efficient Catalysts for Low-Temperature Soot Oxidation

et al. 2018

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Two nanostructured potassium-manganese oxides, with a layered (OL) and tunneled structure (OMS-2), were synthesized and their surface decorated with 1% Pd. All prepared samples were characterized by means of X-ray diffraction, Raman spectroscopy, N 2-BET specific surface area analysis, TPR, SEM/TEM. Catalytic activity in soot combustion in different reaction conditions was investigated (tight contact, loose contact, loose contact with NO addition). The obtained results revealed, that manganese oxides are highly catalytically active in soot combustion, shifting the reaction temperature window by 280 °C for OMS-2 and 300 °C for OL in comparison to the non-catalytic process. Furthermore, Pd promotion is beneficial in all cases, lowering the window of soot combustion compared to the unpromoted oxides, with the most significant effect for loose contact conditions. The difference in activity between tight and loose contacts can be successfully bridged in the presence of NO due to its transformation into NO 2. The particular activity of 1% Pd/OMS-2 and 1% Pd/OL pave the road for their further development towards catalytic system for efficient soot removal in the conditions present in diesel exhaust gases.

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Section: Resultssupporting

confidence: 76%

Nanostructured Potassium-Manganese Oxides Decorated with Pd Nanoparticles as Efficient Catalysts for Low-Temperature Soot Oxidation

et al. 2018

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“…the high mobility of K compounds on the soot surface/the ability to act as a molten salt (sometimes described as a film of metallic K and K 2 O) and, therefore, a very good contact with the soot,…”

Section: Introductionmentioning

confidence: 99%

Catalytic Effect of Potassium Compounds in Soot Oxidation

2017

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The combustion temperatures of soot in particulate filters can be decreased to exhaust gas temperatures by using catalysts. In addition to oxidic catalysts, alkali metal salts are very effective catalysts. Although soot is one of the world's most unwanted byproducts, combustion is still not fully understood. In this study, different soot mixed internally with salt samples were produced. All salts lead to a marked, salt‐ and salt‐content‐dependent decrease of the temperature‐programmed oxidation temperatures of maximum CO + CO2 emissions (Tmax), with K2CO3 being one of the most effective catalysts that leads to a decrease of the Tmax of up to 300 °C. Structural parameters of the internally mixed soot derived by using Raman microspectroscopy, SEM, and scanning mobility particle size analysis did not change significantly; BET areas showed slight trends to lower areas with increased salt content, but no substantial correlations were observed. In contrast, a correlation of the oxidation reactivity to the number distribution of the measured actual fringe lengths by using high‐resolution transmission electron microscopy and the peak areas measured by using EPR spectroscopy was found. Salts lead to a narrowing of the actual fringe length number distributions to lower sizes and to reduced EPR peak areas. This demonstrates that the salts influence the nanostructure of the graphene planes by shortening the planes and further substantiates that soot oxidation is at least partly based on electron transfer and not only oxygen transfer. EPR spectroscopy measurements indicate that the oxidation mechanism is based on a temperature‐dependent chemical equilibrium, which depends on the K+/anion binding strength.

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“…In the case of VOCs, and particularly in the case of the oxidation of the remaining hydrocarbons (HC), the following oxidic systems and compounds have been reported as being active: Co 3 O 4 , MnO 2 , CeO 2 , and CuO [21][22][23][24][25][26][27][28][29][30][31]. The combustion reaction of particulate matter has been extensively studied in recent decades, identifying catalysts with very diverse active phases [32][33][34][35][36][37][38][39][40][41]. A meticulous study of them can be found in a review by A. Bueno Lopez et al [32] and in a more recent review by D. Fino et al [33].…”

Section: Introductionmentioning

confidence: 99%

Zirconia-Supported Silver Nanoparticles for the Catalytic Combustion of Pollutants Originating from Mobile Sources

et al. 2019

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This work presents the physicochemical characterization and activity of zirconia-supported silver catalysts for the oxidation of pollutants present in diesel engine exhaust (propane, propene, naphthalene and soot). A series of silver-supported catalysts AgxZ (x = 1, 5 and 10 wt.%, Z = zirconia) were prepared, which were studied by various characterization techniques. The results show that silver is mainly found under the form of small metal nanoparticles (<10 nm) dispersed over the support. The metallic phase coexists with the AgOx oxidic phases. Silver is introduced onto the zirconia, generating Ag–ZrO2 catalysts with high activity for the oxidation of propene and naphthalene. These catalysts also show some activity for soot combustion. Silver species can contribute with zirconia in the catalytic redox cycle, through a synergistic effect, providing sites that facilitate the migration and availability of oxygen, which is favored by the presence of structural defects. This is a novel application of the AgOx–Ag/ZrO2 system in the combustion reaction of propene and naphthalene. The results are highly promising, given that the T50 values found for both model molecules are quite low.

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K-supported catalysts for diesel soot combustion: Making a balance between activity and stability

Cited by 47 publications

References 54 publications

Nanostructured Potassium-Manganese Oxides Decorated with Pd Nanoparticles as Efficient Catalysts for Low-Temperature Soot Oxidation

Nanostructured Potassium-Manganese Oxides Decorated with Pd Nanoparticles as Efficient Catalysts for Low-Temperature Soot Oxidation

Catalytic Effect of Potassium Compounds in Soot Oxidation

Zirconia-Supported Silver Nanoparticles for the Catalytic Combustion of Pollutants Originating from Mobile Sources

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