Kinetics and mechanism of steady-state catalytic NO + O2 reactions on Pt/SiO2 and Pt/CeZrO2

Marques, Rui; Darcy, Pierre; Costa, Patrick Da; Mellottée, H.; Trichard, Jean-Michel; Djéga‐Mariadassou, Gérald

doi:10.1016/j.molcata.2004.06.023

Cited by 69 publications

(42 citation statements)

References 20 publications

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“…Pt/SiO 2 exhibited a higher reaction rate than Pt/CeO 2 , consistent with results reported by Bernard et al [5]. Table 1 shows that the apparent activation energy (E a ) determined for the Pt/SiO 2 catalyst is 40.6 kJ/mole, which is less than the value of 57.7 kJ/mole reported by Marques et al [17]. This difference may be due to the different chemical state of the Pt in the catalysts studied.…”

Section: Kinetic Studysupporting

confidence: 88%

“…In the present work, Pt should be mainly present in an oxidic state, given the small size of the supported Pt particles (Pt dispersion of 0.80) and that no reduction step was applied; this contrasts with the reduced catalyst studied by Marques et al which possessed a lower Pt dispersion of 0.21. Relative to Pt/SiO 2 , Pt/CeO 2 possesses a slightly lower E a of 31.4 kJ/ mole, this being similar to the E a value of 34.6 kJ/mole reported for Pt/CeZrO 2 [17].…”

Section: Kinetic Studysupporting

confidence: 81%

“…To date the majority of kinetic and mechanistic studies have focused on Pt/Al 2 O 3 , Pt/BaO/Al 2 O 3 and Pt/SiO 2 catalysts [4][5][6][7][8][9][10][11][12][13][14][15][16][17], based on their potential use in automotive applications. In contrast, there have been few reports concerning the properties of Pt supported on CeO 2 .…”

Section: Introductionmentioning

confidence: 99%

“…In this context, current understanding of the properties ofPt/CeO 2 À ZrO 2 is confined to a study by Dje´ga-Mariadassou and co-workers [17], concerning the steady state kinetics of NO oxidation on Pt/Ce 0.25 Zr 0.75 O 2 and Pt/SiO 2 . For both catalysts reaction orders in NO and O 2 were found to be fractional and positive, from which a sequence of elementary steps and a detailed rate equation were proposed.…”

Section: Introductionmentioning

confidence: 99%

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A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

Toops

Graham

et al. 2006

Catal Lett

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NO oxidation was studied over Pt/CeO 2 and Pt/SiO 2 catalysts. Apparent activation energies (E a ) of 31.4 and 40.6 kJ/mole were determined for Pt/CeO 2 and Pt/SiO 2 , respectively, while reaction orders for NO and O 2 were fractional and positive for both catalysts. Pre-treatment of the catalysts with SO 2 caused a decrease in the E a values, while the reaction orders were only slightly changed. In situ DRIFTS measurements indicated that high concentrations of nitrate species were formed on the surface of Pt/CeO 2 during NO oxidation, while almost no surface species could be detected on Pt/SiO 2 . The addition of SO 2 resulted in the formation of a highly stable sulfate at the expense of nitrate species and caused an irreversible loss of catalytic activity for Pt/CeO 2 .

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Section: Kinetic Studysupporting

confidence: 88%

Section: Kinetic Studysupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

Toops

Graham

et al. 2006

Catal Lett

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“…In mehreren Literaturstellen wurde bereits über Deaktivierungseffekte auf Ptbasierten Katalysatoren berichtet, welche der partiellen Oxidation des Edelmetalls zugeschrieben werden [74,83] …”

Section: Platinunclassified

Experimentelle und simulative Untersuchung von Dieseloxidationskatalysatoren bei reversibler Edelmetalloxid-Bildung

Dubbe¹

2018

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DFT‐Based Coverage‐Dependent Model of Pt‐Catalyzed NO Oxidation

Getman

Schneider

2010

ChemCatChem

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A coverage‐dependent, mean‐field microkinetic model of catalytic NO oxidation, NO+0.5 O2⇌NO2, at a Pt(111) surface has been developed, based on large supercell density functional theory (DFT) calculations. DFT is used to determine the overall energetics and activation energies of candidate reaction steps as a function of surface coverage. Surface coverage is found to have a significant but non‐uniform effect on the energetics, pathways, and activation energies of reaction steps involving formation or cleavage of ONO and OO bonds, and inclusion of this coverage dependence is essential for obtaining a qualitatively correct representation of the catalysis. Correlations are used to express all reaction parameters in terms of a single coverage variable θ and steady‐state solutions to the resultant mean‐field models are obtained in the method of DeDonder relations. At conditions representative of NO oxidation catalysis, the surface coverage is predicted to be 0.25≤θ<0.4 ML and to be controlled by equilibrium between gas‐phase NO and NO2 and chemisorbed O. O2 dissociative adsorption (O2(g)→2O*) is rate limiting in the model. The DFT‐based mean‐field model captures many features of the experimentally observed catalysis, and its short‐comings point the way toward more robust models of coverage‐dependent kinetics.

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Kinetics and mechanism of steady-state catalytic NO + O2 reactions on Pt/SiO2 and Pt/CeZrO2

Cited by 69 publications

References 20 publications

A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

Experimentelle und simulative Untersuchung von Dieseloxidationskatalysatoren bei reversibler Edelmetalloxid-Bildung

DFT‐Based Coverage‐Dependent Model of Pt‐Catalyzed NO Oxidation

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