LaCeCo perovskites as catalysts for exhaust gas depollution

Forni, L.; Oliva, Cesare; Vatti, Francesco P.; Kandala, M.A.; Ezerets, A.M.; Вишняков, А.В.

doi:10.1016/0926-3373(95)00039-9

Cited by 46 publications

(27 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…More importantly, along with the second peak of NO, O 2 signal was detected with a proportional amount of NO. This observation is similar with the records by Forni et al [15]. It could be concluded that NO 2 was desorbed above 250 8C, and the detections of both NO and O 2 were due to the fractions of NO 2 molecular bombed by electron beam in the QMAS chamber.…”

Section: Tpd and Drifts Study Of No And O 2 Co-adsorption And Desorptionsupporting

confidence: 81%

See 1 more Smart Citation

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

et al. 2007

View full text Add to dashboard Cite

This paper presents an investigation on the NO oxidation properties of perovskite oxides. La 1Àx Ce x CoO 3 (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4) perovskite-type oxides were synthesized through a citrate method and characterized by XRD, BET and XPS. The catalytic activities were enhanced significantly with Ce substitution, and achieved the best when x was 0.2, but decreased at higher x values. The performed characterizations reveal that the adsorbed oxygen on the surface plays an important role in the oxidation of NO into NO 2 . The surface compounds after the co-adsorption of NO and O 2 at room temperature, were investigated by DRIFTS and TPD experiments. Three species: the bridging nitrate, the hyponitrites and the monodentate nitrate, were formed on the surface. The order of thermal stabilities was as follows: monodentate > hyponitrite > bridging. Among them, only the monodentate nitrate which decomposed at above 300 8C, would desorb NO 2 into the gas phase. When Ce was added, the temperature of monodentate nitrate desorption became low and the adsorption of the other two species decreased. This might be related to the oxidation state of Co on the surface. Analysis by synthesizing the characterization results and catalytic activity data shows that large amounts of adsorbed oxygen, small amount of inactive compounds on the surface and low NO 2 desorption temperature are favorable for the oxidation of NO. #

show abstract

Section: Tpd and Drifts Study Of No And O 2 Co-adsorption And Desorptionsupporting

confidence: 81%

“…On the other hand, similar to the results in refs. [13][14][15], substitution of cerium with increasing values resulted in the appearance of additional phases and a change of perovskite structure itself. For x = 0 and 0.05, the structures were the rhombohedral LaCoO 3 -type (JCPD-ICDD 25-1060); when x !…”

Section: Structural Features Of Catalystsmentioning

confidence: 99%

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Above this percentage, segregation in the perovskite structure is typically observed, which decreases their catalytic activity [46]. According to several studies, partial substitution of perovskites with Ce led to an increase in catalytic oxidation activity for propane [47], carbon monoxide [48], methane [49] and ethanol [50]. Falcon et al [45] investigated the effect of Sr doping on the catalytic activity for complete oxidation of CO of Ln x Ni 1-x O 3 where Ln = Pr, Sm, Eu (with x = 0.01, 0.05 and 0.10) as compared to non-doped LnNiO 3 .…”

Section: Bare Perovskite Materialsmentioning

confidence: 98%

Promotion of Pt Nanoparticles by Lattice Oxygen in SmFeO3 Perovskite Group for Carbon Monoxide and Ethylene Oxidation

et al. 2015

View full text Add to dashboard Cite

The novel Sm 1-x Ce x FeO 3-d (x = 0, 0.01, 0.05) (SCF) perovskites with and without 1 wt% of Pt nanoparticles (NPs) were investigated for carbon monoxide and ethylene oxidation in the temperature range of 25-350°C. All perovskites were predominantly ionic conductors, with ionic conductivities two orders of magnitude higher than the electronic contribution. Furthermore, the cerium doping increases the ionic conductivity of these materials at high temperatures. The bare SCF perovskites possessed catalytic activity for both reactions; however the Pt-supported catalysts had 50-100°C lower light-off temperatures than the corresponding perovskites. More significantly, the enhancement in the catalytic activity of the Pt/SCF family with respect to other Pt-supported catalysts was shown by the lower activation energies, which were 25.7 kJ/mol over Pt/Sm 0.95 Ce 0.05 FeO 3-d and 18.3 kJ/mol over Pt/Sm 0.99 Ce 0.01 FeO 3-d for CO and ethylene oxidation, respectively. The corresponding activation energies for Pt NPs supported on conventional cAl 2 O 3 were 57.1 and 32 kJ/mol, and on ionically conductive yttria-stabilized zirconia (YSZ) were 35.8 and 22 kJ/mol for CO and C 2 H 4 oxidation, respectively. The increased activity was attributed to the high ionic conductivity (O 2-) of the perovskite supports at 100-400°C that facilitates the spontaneous backspillover of O 2-promoters from the lattice to the gas-exposed Pt nanoparticle surface. The promoters alter the adsorption strength of reactants similar to the electrochemical promotion mechanism observed under polarization.

show abstract

“…With the substitutions at 'A' and/or 'B' site with different valence elements creates valences and vacancies, which helps in controlling the mechanism of a reaction. This tailoring possibility with perovskite structure has been used and several compositions have been reported for NO reduction using hydrocarbons or CO as reducing agent [16][17][18][19][20][21][22]. Particularly in the case of three-way catalysis for auto-exhaust emission reduction, perovskite shows activity by participation of lattice oxygen for oxidation and selectively taking oxygen from NO x for filling back the oxygen vacancy formed.…”

Section: Introductionmentioning

confidence: 97%

Nitric Oxide Reduction Using Hydrogen Over Perovskite Catalysts with Promotional Effect of Platinum on Catalytic Activity

et al. 2008

View full text Add to dashboard Cite

The catalytic activities of strontium substituted La 0.7 Sr 0.3 MnO 3 type perovskite catalysts for NO reduction using H 2 as reducing agent has been studied, which is further improved by incorporation of Pt outside (0.1 wt.%Pt/ La 0.7 Sr 0.3 MnO 3 ) and inside (La 0.7 Sr 0.3 Mn 0.97 Pt 0.03 O 3 ) the perovskite lattice structure. Pt shows excellent enhancement in catalytic selectivity towards N 2 when supported on the perovskite. The catalysts were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area. Catalysts evaluations were carried out using thermo-gravimetric analysis coupled with mass spectra (TG-MS).

show abstract

LaCeCo perovskites as catalysts for exhaust gas depollution

Cited by 46 publications

References 19 publications

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

Promotion of Pt Nanoparticles by Lattice Oxygen in SmFeO3 Perovskite Group for Carbon Monoxide and Ethylene Oxidation

Nitric Oxide Reduction Using Hydrogen Over Perovskite Catalysts with Promotional Effect of Platinum on Catalytic Activity

Contact Info

Product

Resources

About