A comparative study of the C3H6+NO+O2, C3H6+O2 and NO+O2 reactions in excess oxygen over Na-modified Pt/γ-Al2O3 catalysts

Yentekakis, I.V.; Tellou, V.; Botzolaki, Georgia; Rapakousios, I.A.

doi:10.1016/j.apcatb.2004.08.017

Cited by 60 publications

(48 citation statements)

References 50 publications

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“…Such a weak partial-pressure dependency of the selectivity has been observed earlier on Rh in DeNO x reactions at high NO coverage. [34] In that case, the usual formation of nitrogen via the recombination of two adjacent chemisorbed nitrogen atoms (from the dissociation of NO) would not operate significantly. The formation of N 2 and N 2 O would probably involve similar adsorbed intermediate species.…”

Section: Pt/sio 2 Catalystsmentioning

confidence: 98%

“…Conversion profiles are reported in Figures 5-7 and 9. According to earlier investigations using a wide variety of hydrocarbons, [34] …”

Section: Catalytic Behaviormentioning

confidence: 98%

“…Concerning kinetics, previous investigations suggest that the extent of interaction between hydrocarbons and noble metal particles may strongly influence the nature of the reaction pathways for the reduction of NO to N 2 . [34] By way of illustration, a weak interaction between alkanes and Pt would lead to high oxygen covering with subsequent formation of surface oxidic Pt species. Consequently, NO x reduction would preferentially occur on alumina and/or at the metalsupport interface between hydrocarbon-derived species and NO 2 to produce N 2 .…”

Section: Catalytic Behaviormentioning

confidence: 99%

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Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates

Pârvulescu

Pârvulescu²,

Endruschat

et al. 2007

ChemPhysChem

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Sol‐gel synthesis of silica and silica–tantalum oxide embedded platinum nanoparticles is carried out using Pt colloids as templates. These colloids are prepared by reduction with Na[AlEt3H] and stabilized with different ligands (ammonium halide derivatives, non‐ionic surfactants with polyether chains, and 2‐hydroxy‐propionic acid). The aim of the present study is to prepare mesoporous silica embedded Pt colloids combining the “precursor concept” with the model of catalyst preparation using preformed spheres. Nanoparticles of Pt incorporated in high surface area mesoporous materials are formed after calcination. Further, it is observed that calcination of these catalysts causes partial aggregation and oxidation of the parent colloids, a process that is largely dependent on the nature of the stabilizing ligands. Several methods have been used for characterization of these materials: adsorption‐desorption isotherms at 77 K, H2 chemisorption, X‐ray diffraction(XRD), 29Si and 13C magic angle spinning (MAS) NMR, ammonia diffuse reflectance Fourier transform infrared spectroscopy (NH3‐DRIFT), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS). It is found that both metal oxide systems exhibit Brønsted acidity (weaker for silica and quite strong for silica–tantalum oxide). In addition, NH3‐DRIFT experiments demonstrate the oxidative properties of the surface. Part of the adsorbed NH4+ species is oxidized to N2O. Testing these catalysts in the reduction of NO and NO2 with isopentane under lean conditions indicate that the activity of these catalysts is indeed dependent on the size of the platinum particles, with those of size 8–10 nm demonstrating the best results. The support likely contributes to this effect, particularly after Ta incorporation into silica.

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Section: Pt/sio 2 Catalystsmentioning

confidence: 98%

“…Conversion profiles are reported in Figures 5-7 and 9. According to earlier investigations using a wide variety of hydrocarbons, [34] …”

Section: Catalytic Behaviormentioning

confidence: 98%

Section: Catalytic Behaviormentioning

confidence: 99%

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Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates

Pârvulescu

Pârvulescu²,

Endruschat

et al. 2007

ChemPhysChem

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“…However, due to the scarcity of Rh and consequently its higher cost, much attention has been recently dedicated to discover means of enhancing (by appropriate structural or surface promoters) the catalytic properties of the other noble metals, Pt and Pd, in order to reduce the total noble metals' loading and minimize or obliterate the use of Rh in TWCs [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of CexZryLazOδ Mixed Oxides on the Structural and Catalytic Behavior of Monometallic Catalytic Converters Under Simulated Exhaust Conditions

et al. 2009

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The effect of CeO 2 , La 2 O 3 and ZrO 2 structural stabilizers/promoters, in the form of Ce x Zr y La z O d mixed oxides, on the catalytic performance and thermal stability of monometallic (Pt), monolithic-type, Al 2 O 3 -washcoated three-way catalytic converters (TWCs) was investigated under simulated exhaust conditions. The evolution of textural, structural and surface behavior of Ce x Zr y La z O d modified TWCs were identified by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and diffuse reflectance infrared spectroscopy (DRIFTS) and appropriately correlated with the catalytic behavior and thermal stability of TWCs.

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“…Many previous studies with supported catalysts have focused on the use of simulated exhaust gas mixtures containing HC/NO/O 2 concentrations in the range 1,000 ppm/1,000 ppm/5% and H 2 , CH 4 , C 2 H 4 or C 3 H 6 reductant over dispersed catalysts in fixed bed or fluidized bed reactors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical promotion of NO reduction by C2H4 in 10% O2 using a monolithic electropromoted reactor with Rh/YSZ/Pt elements

et al. 2008

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The reduction of NO by C 2 H 4 in high excess of O 2 and temperatures 200-300°C was investigated using a monolithic electropromoted reactor (MEPR) with twentytwo Rh/YSZ/Pt parallel plate elements. It was found that at 220-240°C and 10% O 2 the selective catalytic reduction (SCR) of NO can be electropromoted by 450% with near 100% selectivity to N 2 and K NO values up to 2.4. The corresponding rate enhancement ratio of complete C 2 H 4 oxidation is up to 900% with Faradaic efficiency, K CO 2 , values up to 350. The system appears promising for practical applications.

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A comparative study of the C3H6+NO+O2, C3H6+O2 and NO+O2 reactions in excess oxygen over Na-modified Pt/γ-Al2O3 catalysts

Cited by 60 publications

References 50 publications

Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates

Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates

Effect of CexZryLazOδ Mixed Oxides on the Structural and Catalytic Behavior of Monometallic Catalytic Converters Under Simulated Exhaust Conditions

Electrochemical promotion of NO reduction by C2H4 in 10% O2 using a monolithic electropromoted reactor with Rh/YSZ/Pt elements

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A comparative study of the C3H6+NO+O2, C3H6+O2 and NO+O2 reactions in excess oxygen over Na-modified Pt/γ-Al2O3 catalysts

Cited by 60 publications

References 50 publications

Mesoporous Pt–SiO2 and Pt–SiO2–Ta2O5 Catalysts Prepared Using Pt Colloids as Templates

Mesoporous Pt–SiO2 and Pt–SiO2–Ta2O5 Catalysts Prepared Using Pt Colloids as Templates

Effect of CexZryLazOδ Mixed Oxides on the Structural and Catalytic Behavior of Monometallic Catalytic Converters Under Simulated Exhaust Conditions

Electrochemical promotion of NO reduction by C2H4 in 10% O2 using a monolithic electropromoted reactor with Rh/YSZ/Pt elements

Contact Info

Product

Resources

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Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates

Mesoporous Pt–SiO₂ and Pt–SiO₂–Ta₂O₅ Catalysts Prepared Using Pt Colloids as Templates