• Article dans une revue

NMR cogwheel phase cycling determination with web tools: Amplitude-modulated z-filter MQMAS sequence

Yannick Millot, Redouane Hajjar, Pascal P. Man

Our recent method based on the use of web tools (XML and XSLT) for constructing cogwheel phase cycles is extended to the selection of two sym. coherence transfer pathways in the case of an amplitude-modulated z-filter MQMAS sequence. For all spins (I=3/2, 5/2, 7/2 and 9/2) and all MQ expts. we…

Solid State Nuclear Magnetic Resonance, 2010, 38 (1), pp.19-26. ⟨10.1016/j.ssnmr.2010.06.001⟩. ⟨hal-00604781⟩

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Light olefin transformation over ZSM-5 zeolites with different acid strengths - A kinetic model

P. Oliveira, P. Borges, R. Ramos Pinto, M. A. N. D. A. Lemos, F. Lemos, Jacques C. Vedrine, F. Ramoa Ribeiro

The authors analyzed the influence of the acidity of a ZSM-5 catalyst on the catalytic transformation of various short-chain olefins (ethylene, propylene and 1-butene). Four ZMS-5 catalysts with different acid strength distributions were studied at different temps. and partial pressures. The…

Applied Catalysis A : General, 2010, 384 (1-2), pp.177-185. ⟨10.1016/j.apcata.2010.06.032⟩. ⟨hal-00604786⟩

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Extension of a kinetic model for NO oxidation and NOx storage to fixed-bed Pt/Ba/Al2O3 catalysts

Nikola Rankovic, Andre Nicolle, David Berthout, Patrick da Costa

Following our work on modeling of monolith catalysts, we herein focus on developing a fixed-bed reactor model in the AMESim modeling platform. A kinetic model for NO oxidn. and NOx storage over Pt/Ba/Al2O3 recently developed in the literature was successfully implemented and validated against the…

Catalysis Communications, 2010, 12 (1), pp.54-57. ⟨10.1016/j.catcom.2010.07.012⟩. ⟨hal-00604793⟩

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CO- and N2-FTIR Characterisation of Oxidised Rhodium Species Supported on Ce0.68Zr0.32O2

Céline Fontaine-Gautrelet, Jean-Marc Krafft, Olivier Gorce, Françoise Villain, Gérald Djéga-Mariadassou, Cyril Thomas

The identification of Rh oxidised species of a Rh(0.29)/Ce0.68Zr0.32O2 catalyst, exhibiting peculiar CO-O2 kinetics [Manuel et al., J. Catal. 2004, 224, 269], is addressed. For this purpose, various catalysts are studied by XANES, CO- and N2-FTIR, and benzene hydrogenation. The results obtained,…

Physical Chemistry Chemical Physics, 2006, 8, pp.3732-3740. ⟨10.1039/b601926a⟩. ⟨hal-00091039⟩

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Evidence for Rh electron-deficient atoms (Rhdelta+) as the catalytic species for CO oxidation when supported on Ce0.68Zr0.32O2: a combined N2-FTIR, benzene hydrogenation and kinetic study

Céline Fontaine-Gautrelet, Jean-Marc Krafft, Gérald Djéga-Mariadassou, Cyril Thomas

The characterization of two low-loaded Rh(wt%)/Ce0.68Zr0.32O2 samples (Rh(0.29)/CZ and Rh(0.32)/CZ) was performed via N2-FTIR and benzene hydrogenation before being investigated for CO oxidation activity and kinetics. N2-FTIR allows characterization of both RhΔ+ (νN2 = 2295 cm-1) and Rh0 (νN2 =…

Journal of Catalysis, 2007, 247, pp.34-42. ⟨10.1016/j.jcat.2007.01.005⟩. ⟨hal-00157019⟩

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Kinetic study of the hydrodesulfurization of dibenzothiophene over molybdenum carbides supported on functionalized carbon black composite Influence of indole

A. Hynaux, Celine Sayag, S. Suppan, J. Trawczynski, M. H. Lewandowski, A. Szymanska-Kolasa, G. Djéga-Mariadassou

Different carbon black composite (CBC) supported molybdenum carbides were synthesized. The support was functionalized with nitric acid at different pH of the impregnation solution (pH 5.2; 0), in order to improve the active phase dispersion. After characterization of these supported catalysts, the…

Applied Catalysis B: Environmental, 2006, 72, pp.62-70. ⟨10.1016/j.apcatb.2006.09.019⟩. ⟨hal-00128025⟩

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Hydrodenitrogenation of indole over Mo2C catalyst: Insights into mechanistic events through DFT modeling

Witold Piskorz, Grzegorz Adamski, Andrzej Kotarba, Zbigniew Sojka, Céline Sayag, G. Djéga-Mariadassou

The molecular reaction mechanism of hydrodenitrogenation of indole was studied using density-functional theory calculations of the adsorbed o-ethylaniline surrounded by mobile hydrogen atoms. It was found that the hydrogenation of o-ethylaniline occurs through two steps: consisting in…

Catalysis Today, 2006, 119, pp.39-43. ⟨10.1016/j.cattod.2006.08.050⟩. ⟨hal-00128043⟩

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Characterization of Mo2C-WO2 composite catalysts for bifunctional isomerization: a new pulse method to quantify acid sites

Claude Potvin, Anne-Félicie Lamic Chae-Ho Shin Gérald Djega-Mariadassou Claude Potvin

Applied Catalysis A : General, 2006, 302, pp.5. ⟨10.1016/j.apcata.2005.12.006⟩. ⟨hal-00022217⟩

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Real time monitoring of the evolution of Ni2+ environment in faujasite upon rehydration by in situ dispersive-EXAFS.

Jean-François Groust, Catherine Pommier, Lorenzo Stievano, François Villain, Christine Giorgetti, François Baudelet, Pascale Massiani

The evolution of both oxygen and framework tetrahedral shells around Ni2+ cations in faujasite upon rehydration can be described in real time thanks to in situ dispersive-EXAFS. Such type of analysis permits precise experimental description of the coordination environment of cations in zeolite…

Catalysis Letters, 2005, 102, pp.257-260. ⟨10.1007/s10562-005-5865-3⟩. ⟨hal-00020239⟩

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Solid base catalysts obtained from hydrotalcite precursors, for Knoevenagel synthesis of cinamic acid and coumarin derivatives

E. Angelescu, Octavian Dumitriu Pavel, Ruxandra Bırjega, Rodica Zavoianu, Guylène Costentin, Michel Che

The goal of this paper was to study the synthesis of the cinamic acid, coumarin-3-carboxilic acid and their ethylesters by Knoevenagel condensation using the solid base catalysts obtained from calcined Mg–Al, Mg–Al + Ln (Ln = Dy, Gd) and Li–Al hydrotalcites, under solvent free conditions.…

Applied Catalysis A : General, 2006, 308, pp.13-18. ⟨10.1016/j.apcata.2006.04.011⟩. ⟨hal-00112131⟩