Activity, selectivity and stability of praseodymium-doped CeO2 for chlorinated VOCs catalytic combustion

Rivas, Beatriz de; Guillén-Hurtado, Noelia; López‐Fonseca, Rubén; Coloma, Fernando; Garcı́a-Garcı́a, Avelina; Gutiérrez-Ortiz, José I.; Bueno‐López, Agustín

doi:10.1016/j.apcatb.2012.03.029

Cited by 85 publications

(56 citation statements)

References 26 publications

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“…Two main bands corresponding to the Pt 4f7/2 level (at lower binding energies) and Pt 4f5/2 level (at higher binding energies) are shown in Figure 3. All of the catalysts present the main Pt 4f7/2 peak at 73.5-74.0 eV, which can be attributed to either Pt 2+ or Pt 4+ [31]. No significant differences are observed in the oxidation state of Pt or in the Ptsupport interaction for catalysts containing pure ceria as the support.…”

Section: Xps and H 2 Chemisorption Characterizationmentioning

confidence: 82%

“…The creation of vacancies on the Ce0.9Pr0.1O2 supports occurs due to the higher reducibility of the Pr 4+ cation compared to the Ce 4+ cation. It is also important to highlight that the position of the band at 450-460 cm -1 is shifted to lower Raman shift when praseodymium is introduced in the ceria support, this also being evidence for the presence of a higher concentration of 3+ cations in the praseodymium-containing supports [31][32][33]. reported by other authors and has been attributed to Pr leaching and subsequent precipitation during the noble metal impregnation step [34].…”

Section: X-ray Diffraction N 2 Adsorption At -196 ºC and Raman Spectmentioning

confidence: 97%

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Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Rico-Pérez

Bueno‐López

Kim

et al. 2015

Applied Catalysis B: Environmental

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Model Pt/Ce0.9Pr0.1O2 and Pt/CeO2 NOx storage-reduction catalysts were prepared via nitrate calcination, co-precipitation and carbon-templating routes.Raman spectroscopic data obtained on the catalysts indicated that the introduction of praseodymium into the ceria lattice increased the concentration of defect sites (vacancies), arising from the higher reducibility of the Pr 4+ cation compared to Ce 4+ . For the Pr-promoted samples, H2-TPR profiles contained high temperature bulk reduction peaks which were less pronounced compared with their ceria analogs, indicating that the presence of praseodymium enhances oxygen mobility due to the creation of lattice defects. Under lean-rich cycling conditions, the cycle-averaged NOx conversion of the Pt/Ce0.9Pr0.1O2samples was in each case substantially higher than that of the Pt/CeO2 analog, amounting to a difference of 10-15% in the absolute NOx conversion in some cases. According to DRIFTS data, a double role can be assigned to Pr doping; on the one hand, Pr accelerates the oxidation of adsorbed NOx species during the lean periods. On the other hand, Pr doping destabilizes the adsorbed NOx species during the rich periods, and the kinetics of nitrate decomposition are faster on Pt/Ce0.9Pr0.1O2, leading to improved catalyst regeneration. These results suggest that ceria-based mixed oxides incorporating Pr are promising materials for NOx storage-reduction catalysts intended for low temperature operation.

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Section: Xps and H 2 Chemisorption Characterizationmentioning

confidence: 82%

Section: X-ray Diffraction N 2 Adsorption At -196 ºC and Raman Spectmentioning

confidence: 97%

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Rico-Pérez

Bueno‐López

Kim

et al. 2015

Applied Catalysis B: Environmental

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“…Textural, structural and surface characterisation of the four catalysts studied in this work was reported in previous publications [9][10][11]13]. A summary of some physico-chemical properties is compiled on level considering the thermodynamic equilibrium of the NO oxidation reaction to NO 2 is also represented in Figure 1a as a dotted line, showing that this reaction is thermodynamically favoured at low temperature but not at high temperature.…”

Section: Resultsmentioning

confidence: 99%

Behavior of different soot combustion catalysts under NOx/O2. Importance of the catalyst–soot contact

Guillén-Hurtado

López-Suárez

Bueno‐López

et al. 2013

Reac Kinet Mech Cat

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Four different catalysts (Pt/Al 2 O 3 , Ce 0.8 Zr 0.2 O 2 , PrO 2-x and SrTiCuO 3 ) have been investigated in a laboratory scale to evaluate its potential as diesel soot catalysts under different experimental conditions, which simulate the situation found in a Continuously Regeneration Technology trap (dual-bed configuration of catalyst and soot) or a CatalystCoated Filter system, (single-bed configuration, both catalyst and soot particles mixed under loose-contact mode). Under dual-bed configuration, the catalysts' behaviours towards soot combustion are very similar, despite of the differences observed in the NO 2 production profiles. However, under single-bed configuration, there are important differences in the soot combustion activities and in the NO 2 slip profiles. The configurations chosen have an enormous impact on CO/(CO+CO 2 ) ratios of combustion products as well. The most active catalyst under NOx+O 2 is PrO 2-x combining high contribution of active oxygen-assisted soot combustion as well as high NO 2 production activity along the catalytic bed.

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“…In particular, Pr-doped CeO 2 is a suitable catalyst for the formation of a solid solution, 30,31 because the structures of CeO 2 and Pr 6 O 11 are uorite-like. In addition, the Ce 4+ ionic radius (0.097 nm) is considerably similar to that of Pr 4+ (0.096 nm), and all of the atoms can exist with the mixed oxidation states of 3+ and 4+ in CePr solid solution.…”

Section: 14mentioning

confidence: 99%

Design structure for CePr mixed oxide catalysts in soot combustion

Fan

Zhu

et al. 2017

RSC Adv.

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Four CePr mixed oxides with different structures were designed and synthesized using a solid-phase grinding method: a uniform solid solution of Ce and Pr (CePr-NN), Pr 6 O 11 -coated CeO 2 (CePr-NO), CeO 2 -coated Pr 6 O 11 (CePr-ON), and particle packing of CeO 2 and Pr 6 O 11 (CePr-OO) were obtained, and characterized by XRD, H 2 -TPR, TEM and TG. The results show that CePr-NN exhibits the best low temperature catalytic activity among the CePr catalysts. CeO 2 is the major active phase on the surface of the CePr catalysts, and the use of Pr 6 O 11 as the framework maintains the thermal stability of the CePr composite oxide. Moreover, both the oxygen storage capacity and mobility of the active oxygen of the catalyst were improved with the incorporation of Pr into CeO 2 , resulting in a higher combustion rate. The "molten state" which appeared during the preparation when nitrate was used as the precursor, plays a significant role in the migration of Ce and Pr, and is the premise of forming different structures of solid solution or coating structure.

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Activity, selectivity and stability of praseodymium-doped CeO2 for chlorinated VOCs catalytic combustion

Cited by 85 publications

References 26 publications

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Behavior of different soot combustion catalysts under NOx/O2. Importance of the catalyst–soot contact

Design structure for CePr mixed oxide catalysts in soot combustion

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