Direct decomposition of NO into N2 and O2 on BaMnO3-based perovskite oxides

Iwakuni, Hideharu; Shinmyou, Yusuke; Yano, Hiroshi; Matsumoto, Hiroshige; Ishihara, Tatsumi

doi:10.1016/j.apcatb.2007.02.020

Cited by 109 publications

(72 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The chemical properties of the perovskite materials are also known for their flexible characteristics which are associated with their A and/or B site substitution capabilities and availability of a wide variety of sub-stoichiometric structures [6]. The catalytic efficiencies of perovskite materials for NO and N 2 O reduction into N 2 were demonstrated by several studies [7][8][9][10][11][12][13]. Moreover, these materials play an efficient role in the catalytic NO oxidation under lean conditions even in the absence of a noble metal [14,15].…”

Section: Introductionmentioning

confidence: 99%

Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

Say

Doğaç

Vovk

et al. 2014

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

a b s t r a c tPerovskite-based materials (LaMnO 3 , Pd/LaMnO 3 , LaCoO 3 and Pd/LaCoO 3 ) were synthesized, characterized (via BET, XRD, Raman spectroscopy, XPS and TEM) and their NO x (x = 1,2) adsorption characteristics were investigated (via in-situ FTIR and TPD) as a function of the nature of the B-site cation (i.e. Mn vs Co), Pd/PdO incorporation and H 2 -pretreatment. NO x adsorption on of LaMnO 3 was found to be significantly higher than LaCoO 3 , in line with the higher SSA of LaMnO 3 . Incorporation of PdO nanoparticles with an average diameter of ca. 4 nm did not have a significant effect on the amount of NO 2 adsorbed on fresh LaMnO 3 and LaCoO 3 . TPD experiments suggested that saturation of fresh LaMnO 3 , Pd/LaMnO 3 , LaCoO 3 and Pd/LaCoO 3 with NO 2 at 323 K resulted in the desorption of NO 2 , NO, N 2 O and N 2 (without O 2 ) below 700 K, while above 700 K, NO x desorption was predominantly in the form of NO + O 2 . Perovskite materials were found to be capable of activating N-O linkages typically at ca. 550 K (even in the absence of an external reducing agent) forming N 2 and N 2 O as direct NO x decomposition products. H 2 -pretreatment yielded a drastic boost in the NO oxidation and NO x adsorption of all samples, particularly for the Cobased systems. Presence of Pd further boosted the NO x uptake upon H 2 -pretreatment. Increase in the NO x adsorption of H 2 -pretreated LaCoO 3 and Pd/LaCoO 3 surfaces could be associated with the electronic changes (i.e. reduction of B-site cation), structural changes (surface reconstruction and SSA increase), reduction of the precious metal oxide (PdO) into metallic species (Pd), and the generation of oxygen defects on the perovskite. Mn-based systems were more resilient toward B-site reduction. Pd-addition suppressed the B-site reduction and preserved the ABO 3 perovskite structure.

show abstract

Section: Introductionmentioning

confidence: 99%

Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

Say

Doğaç

Vovk

et al. 2014

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

show abstract

“…The reports suggested that oxide-supported Pd catalysts [10] and Cu-ZSM-5 [11] appeared as the potential catalysts which catalytically convert 50-95% NO in the temperature range of 400-700 • C. Very recently, Fe-Mn/H-beta catalysts were reported to effectively decompose NO x in 300-400 • C in the presence of O 2 and CO 2 with the conversion of 25-45% [12]. It is worth mention-ing that BaMnO 3 -based dopant perovskite oxides can efficiently convert NO to N 2 , O 2 and NO 2 , while the temperature required is high, usually 600-800 • C [13,14], and the decomposition is severely affected by the presence of CO 2 , H 2 O or O 2 [15,16]. There was only one paper reporting that a particular mixed oxide catalyst derived from CoNiAl-HTlc is very active for NO direct decomposition, with ca.…”

Section: Direct Decompositionmentioning

confidence: 99%

“…In our opinion, the major reason is the low selectivity of NO decomposition to N 2 and O 2 . For example, during direct decomposition of NO to N 2 and O 2 , NO 2 and N 2 O are always the byproducts, and sometimes are the main components [4,13,14]. The second reason is the high decomposition temperature (600-900 • C) for high NO x conversion (>80%), so that the practical application of the catalysts for the car exhaust treatment becomes impossible.…”

Section: Direct Decompositionmentioning

confidence: 99%

NO decomposition, storage and reduction over novel mixed oxide catalysts derived from hydrotalcite-like compounds

Yu¹,

Cheng²,

Yan³

et al. 2009

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

mentioning

confidence: 99%

“…In some of conventional catalysts, it has been suggested that the removal of surface oxygen can be easily achieved when the reduction of the tetravalent cation to the trivalent state proceeds easily. 4,5,8 ammonium carbonate solution with stirring, adjusting the total amount of cations to be 10 mmol. The pH value of the mixture was adjusted to 10 by the dropwise addition of aqueous ammonia.…”

mentioning

confidence: 99%

Direct Decomposition of NO on C-type Cubic Rare Earth Oxides Based on Y2O3

Tsujimoto¹,

Mima²,

Masui³

et al. 2010

Chemistry Letters

View full text Add to dashboard Cite

C-type cubic (Y 0.99¹x Tb x Ba 0.01 ) 2 O 2.99+¤ (0¯x¯0.4) catalysts were prepared by coprecipitation. The NO decomposition activities at 1173 K were higher than that of (Gd 0.7 Y 0.26 -Ba 0.04 ) 2 O 2.96 reported previously. The highest catalytic activity was obtained for (Y 0.69 Tb 0.3 Ba 0.01 ) 2 O 2.99+¤ , and 100% NO conversion into N 2 and O 2 was realized at 1173 K on this catalyst. Furthermore, the conversion ratio was maintained as high as 70.8% even in the presence of 5 vol % oxygen.The emission of nitrogen oxides (NO x ) is strictly regulated, because they are not only harmful to human beings but also responsible for photochemical smog and acid rain. The NO x species in the exhaust gas emitted at high temperatures is principally thermodynamically stable NO and the amount of NO 2 is negligible. Accordingly, research should be focused on the NO decomposition in the case of catalytic NO x remediation.For the methods of NO removal, selective catalytic reduction processes using ammonia, urea, or hydrocarbons are the mainstream procedures.1 In these processes, the decomposition efficiency is sufficient, and the reaction process is stable at high temperatures. However, separate specialized equipment is necessary to supply the reducing agents and secure control is indispensable, because ammonia is both toxic and flammable.In contrast to the above methods that utilize selective catalytic reduction, direct decomposition of NO into N 2 and O 2 (2NO ¼ N 2 + O 2 ) is an appropriate route for NO removal, because this process is simple and reductants mentioned above are not required. A number of materials have been reported as active catalysts for direct NO decomposition, such as zeolites, 2 perovskites, 35 and other mixed or complex oxides. 614 However, the activity of conventional catalysts for NO decomposition decreases in the presence of oxygen, due to strong oxygen adsorption.In contrast, it was found that C-type cubic rare earth oxides based on Gd 2 O 3 , (Gd 1¹x¹y Y x Ba y ) 2 O 3¹y (0¯x¯0.26, 0¯y0.08), can exhibit higher activity for direct NO decomposition than that of the perovskite-type catalysts in the presence of oxygen, as reported in our previous study. 14,15 There are three types of crystal structure in rare earth oxide, namely, A-(hexagonal), B-(monoclinic), and C-type (cubic), according to the ionic size of the respective rare earth element. 16 The lattice volume of the rare earth oxides increases in the order of Atype < B-type < C-type, and for this reason the C-type structure possesses the largest interstitial open space suitable for NO decomposition among the three types.It has been generally accepted that oxide vacancies in the catalyst play an important role in the direct catalytic decomposition of NO. 37 Additional introduction of oxide anion vacancies by partial substitution of the trivalent rare earth cations with divalent Ba 2+ ions will enhance the catalytic activity. In some of conventional catalysts, it has been suggested that the removal of surface oxygen can be easily achieved when...

show abstract

Direct decomposition of NO into N2 and O2 on BaMnO3-based perovskite oxides

Cited by 109 publications

References 24 publications

Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

Palladium doped perovskite-based NO oxidation catalysts: The role of Pd and B-sites for NOx adsorption behavior via in-situ spectroscopy

NO decomposition, storage and reduction over novel mixed oxide catalysts derived from hydrotalcite-like compounds

Direct Decomposition of NO on C-type Cubic Rare Earth Oxides Based on Y2O3

Contact Info

Product

Resources

About