Potential rare-earth modified CeO2 catalysts for soot oxidation

Kamasamudram, Krishna; Bueno‐López, Agustín; Makkee, Michiel; Moulijn, Jacob A.

doi:10.1007/s11244-007-0182-2

Cited by 43 publications

(26 citation statements)

References 13 publications

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“…In particular, the presence of oxygen vacancies in the CZ and CH samples were identified from Raman and UV-Vis DRS studies. These results correlate with the activity measurements and are in line with earlier reports [21,25,28]. There seems to be a similarity in the behaviour of ceriabased catalysts for oxidation of CO and the soot.…”

Section: Resultssupporting

confidence: 92%

“…Loose contact did not show a significant decrease in the soot oxidation temperature irrespective of the catalyst employed, which was in agreement with earlier reports [20][21][22]. Apparently, when the soot particle is not in close contact with the catalyst surface, the active oxygen cannot be transferred to the soot particle [25,27,28]. The active oxygen involved for soot combustion comes from two ways: the gaseous oxygen and the oxygen released from the bulk of the catalysts.…”

Section: Resultssupporting

confidence: 90%

“…The active oxygen involved for soot combustion comes from two ways: the gaseous oxygen and the oxygen released from the bulk of the catalysts. The dissociation centers for the adsorption of oxygen provided by the metal oxides also contribute for the observed better catalytic activity [21,28]. The high catalytic activity of CeO 2 for soot oxidation in air was attributed to the generation of highly active oxygen from the lattice due to the oxygen exchange between gas phase O 2 and oxygen in the oxide framework, as mentioned [21], and the redox cycle Ce 3+ /Ce 4+ seems to play an important role in the oxygen exchange process.…”

Section: Resultsmentioning

confidence: 99%

“…The activity measurements were performed in 'tight contact' (ground in agate mortar) condition with catalyst-soot mixtures in 4:1 wt/wt ratio [23,28]. The model soot, Printex U, used in this work was provided by Degussa.…”

Section: Activity Measurementsmentioning

confidence: 99%

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Catalytic Efficiency of Ceria–Zirconia and Ceria–Hafnia Nanocomposite Oxides for Soot Oxidation

et al. 2008

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The catalytic oxidation of soot particulates has been investigated over CeO 2 , CeO 2 -ZrO 2 and CeO 2 -HfO 2 nanocomposite oxides. These oxides were synthesized by a modified precipitation method employing dilute aqueous ammonia solution. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and BET surface area methods. The soot oxidation has been evaluated by a thermogravimetric method under 'tight contact' conditions. The XRD results revealed formation of cubic CeO 2 , Ce 0.75 Zr 0.25 O 2 and Ce 0.8 Hf 0.2 O 2 phases in case of CeO 2 , CeO 2 -ZrO 2 and CeO 2 -HfO 2 samples, respectively. TEM studies confirm the nanosized nature of the catalysts. Raman measurements suggest the presence of oxygen vacancies, lattice defects and oxide ion displacement from normal ceria lattice positions. UV-Vis DRS studies show presence of charge transfer transitions Ce 3+ /O 2-and Ce 4+ /O 2-respectively. The catalytic activity studies suggest that the oxidation of soot could be enhanced by incorporation of Zr 4+ and Hf 4+ into the CeO 2 lattice. The CeO 2 -HfO 2 combination catalyst exhibited better activity than the CeO 2 -ZrO 2 . The observed high activity has been related to the nanosized nature of the composite oxides and the oxygen vacancy created in the crystal lattice.

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Activity Measurementsmentioning

confidence: 99%

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Catalytic Efficiency of Ceria–Zirconia and Ceria–Hafnia Nanocomposite Oxides for Soot Oxidation

et al. 2008

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“…It is also easy to find that the catalytic activity of CRX is similar to that of ZRX under loose contact condition, but it is remarkable better under tight contact condition, which can be explained by this reason as well. It it notable that a more detailed study was recently carried out by Makkee et al [30]. They pointed out that the meso/micro pore a Calculation method was presented in [23] b Obtained by dividing the CO 2 produced in 2nd CO pulse by the time scale 5s c For CRS, since the surface oxygen had not been totally consumed during the 1st CO pulse, the left surface oxygen was subtracted from the CO 2 production in the 2nd CO pulse when calculating the oxygen release rate …”

Section: Relationship Between Surface Area and Soot Oxidationmentioning

confidence: 99%

Role of Surface Area in Oxygen Storage Capacity of Ceria–Zirconia as Soot Combustion Catalyst

Liang

et al. 2007

Catal Lett

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Two thermal stable phases, Ce 0.75 Zr 0.25 O 2 and Ce 0.16 Zr 0.84 O 2 , with different surface area were prepared by coprecipitation. The oxygen storage capacity (OSC) measurements were carried out at 500°C under both transient (CO-O 2 cycle at 0.05, 0.1 and 0.25 Hz) and stationary reaction conditions (CO pulse). In the oxygen storage/release process, the rate-determine step is surface reactions when the specific surface area is lower than 60 m 2 /g. When the surface area increases further, the influence of surface area is less important. The increased surface area favors diesel soot catalytic combustion via providing more redox sites to activate adsorbed oxygen. Nevertheless, this effect is less important when the specific surface area is larger than 40 m 2 /g, especially under loose contact condition.

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Research Advances in Rare Earth Oxide‐Based Catalysts for Soot Combustion

Ma,

Guo,

Xiong

et al. 2024

ChemCatChem

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Environmental issues exert a significant influence on the human life. Soot particles have attracted attention as a major source of pollution. Significant progress has been made in the research of efficient soot combustion catalysts. The distinctive bonding properties on the 4f orbitals of rare earth elements exhibit excellent catalytic performance for soot combustion. This comprehensive review explores recent advancements in the design of catalysts based on rare earth oxides, with a specific focus on various catalytic materials (La‐based, Ce‐based, Pr‐based and other rare earth elements), synthesis methods, catalyst morphology, catalytic performance and the intricate mechanisms governing their performance in catalytic soot combustion. The activity and selectivity of different rare earth catalysts in various reaction atmospheres are also summarized in the article. Finally, the challenges associated with rare earth oxide‐based catalysts and their potential for future development in the soot combustion are highlighted. This review establishes a fundamental basis for the further design of catalytic materials that exhibit enhanced efficiency and stability.

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Potential rare-earth modified CeO2 catalysts for soot oxidation

Cited by 43 publications

References 13 publications

Catalytic Efficiency of Ceria–Zirconia and Ceria–Hafnia Nanocomposite Oxides for Soot Oxidation

Catalytic Efficiency of Ceria–Zirconia and Ceria–Hafnia Nanocomposite Oxides for Soot Oxidation

Role of Surface Area in Oxygen Storage Capacity of Ceria–Zirconia as Soot Combustion Catalyst

Research Advances in Rare Earth Oxide‐Based Catalysts for Soot Combustion

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