Determination of Mechanism for Soot Oxidation with NO on Potassium Supported Mg‐Al Hydrotalcite Mixed Oxides

Zhang, Yexin; Su, Qingyun; Li, Qian; Wang, Zhongpeng; Gao, Xiyan; Zhang, Zhaoliang

doi:10.1002/ceat.201100291

Cited by 17 publications

(14 citation statements)

References 29 publications

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“…The reaction between the C ⁄ [O] intermediate and either O ad or gaseous O 2 produces CO 2 through reaction (3) or (4), reproducing the reactive C f sites on the soot surface. Ketene groups, a carbon-oxygen complex containing the structure of C@C@O, were first reported as intermediates for soot combustion on K/MgAlO catalysts in our previous work [8][9][10]. Over the years, a variety of catalytic materials, mainly transition metal oxides [11], mixed metal oxides [7,12] as well as rare earth metal oxides [6,13] have been reported to be basically active in soot oxidation.…”

Section: Introductionmentioning

confidence: 99%

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

Wang

Zhu

et al. 2016

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

Wang

Zhu

et al. 2016

Journal of Colloid and Interface Science

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“…Apart from the nature of the active sites, the reaction intermediates play an important role in the elucidation of the reaction mechanism. Ketene groups, a carbon–oxygen complex containing the structure of C = C = O, were first reported as intermediates for soot combustion on K/MgAlO catalysts in our previous work 24 25 26 . The question is whether ketene species are common reaction intermediates when K + is present?…”

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confidence: 99%

A unified intermediate and mechanism for soot combustion on potassium-supported oxides

Wang

Xin

et al. 2014

Sci Rep

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The soot combustion mechanism over potassium-supported oxides (MgO, CeO2 and ZrO2) was studied to clarify the active sites and discover unified reaction intermediates in this typical gas-solid-solid catalytic reaction. The catalytically active sites were identified as free K+ rather than K2CO3, which can activate gaseous oxygen. The active oxygen spills over to soot and forms a common intermediate, ketene, before it was further oxidized into the end product CO2. The existence of ketene species was confirmed by density functional theory (DFT) calculations. The oxygen spillover mechanism is proposed, which is explained as an electron transfer from soot to gaseous oxygen through the active K+ sites. The latter mechanism is confirmed for the first time since it was put forward in 1950, not only by ultraviolet photoelectron spectroscopy (UPS) results but also by semi-empirical theoretical calculations.

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“…These facts suggest that the ionic nitrite may be consumed with the production of the ketene group. In other words, the ionic nitrite on K 0.2 -Ce 0.5 Mn 0.5 O 2 interacts with the free carbon sites on the soot to form the ketene group, which can be described as 36 :…”

Section: Resultsmentioning

confidence: 99%

Study on oxidation activity of Ce–Mn–K composite oxides on diesel soot

Huang¹,

Xiao²,

Liu³

et al. 2020

Sci Rep

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As an effective method, diesel particulate filter (DPF) technology has a great contribution in reducing soot emissions from diesel engines. To achieve passive regeneration of DPF at low temperatures, K-doped ce 0.5 Mn 0.5 o 2 catalysts were synthesized using sol-gel method. The effect of K-doped catalysts-K z-ce 0.5 Mn 0.5 o 2-on the oxidation of soot had been studied by thermogravimetric analysis, and the corresponding catalytic properties were evaluated based on X-ray diffraction (XRD), hydrogen temperature programmed reduction (H 2-TPR), O 2 temperature programmed desorption (O 2-TPD) Raman spectroscopy (Raman), Brunauer-Emmett-Teller (BET) and Fourier-Transform-Infrared (FTIR). The results showed that K doping facilitated the oxidation of diesel particulate matter, which was indicated by the entire mass loss curve shifting to lower temperatures. K 0.2-ce 0.5 Mn 0.5 o 2 showed the best performance among the series of K-doped catalysts. Compared with the findings for Ce 0.5 Mn 0.5 o 2 , the ignition temperature of soot oxidation (T i) had been lowered by 28 ℃, and the maximum peak combustion temperature (T m) of the dry soot decreased by 61 °C. Furthermore, compared with the ce 0.5 Mn 0.5 o 2-catalyzed reaction, K doping led to a lower activation energy and significantly improved pre-exponential factor. The minimum reaction activation energy of 27.46 kJ/mol was exhibited by K 0.2-ce 0.5 Mn 0.5 o 2. Diesel vehicles are currently attracting interest owing to their distinctive characteristics of superior power performance and fuel economic properties 1-3 while the pollutants contained in diesel exhaust gas, particularly soot, pose hazards to human's living environment and become one of the source of greenhouse gas which leads to global warming. Therefore, finding proper ways to cut down soot emissions from diesel engines become one of the researching hotpots in the study progress of diesel vehicles, that' why many researchers studied diesel particulate filters (DPF), an effective methods of lowering soot emissions by passive regeneration by chemical catalysis and improving the temperature of the diesel exhaust which is sufficient for soot to burn out. Hence, selecting a suitable catalyst is the key challenge for regeneration 4-8. It is well known that the utilization rate of rare earth resources is low, despite their abundance. CeO 2 plays an important role in three-way catalysts owing to its excellent oxygen storage and release properties 9. Generally, CeO 2 performs as an oxygen buffer to store excess oxygen quickly as the oxygen concentration in the exhaust gas is increasing to higher level, and releasing oxygen promptly at low oxygen concentrations 10-12. In addition, CeO 2 is a promising noble metal substitute for improving the anti-poisoning performance and high temperature durability of catalysts 13,14. The technology of Ce-based catalysts is still constantly improving after decades of development. The unique chemical and physical properties of rare earth-based catalysts present due to their electronic ener...

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Determination of Mechanism for Soot Oxidation with NO on Potassium Supported Mg‐Al Hydrotalcite Mixed Oxides

Cited by 17 publications

References 29 publications

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

Catalytic combustion of soot particulates over rare-earth substituted Ln2Sn2O7 pyrochlores (Ln = La, Nd and Sm)

A unified intermediate and mechanism for soot combustion on potassium-supported oxides

Study on oxidation activity of Ce–Mn–K composite oxides on diesel soot

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