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L. Vivier

Bio: L. Vivier is an academic researcher from University of Poitiers. The author has contributed to research in topics: Catalysis & Hydrogenolysis. The author has an hindex of 15, co-authored 27 publications receiving 750 citations.

Papers
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TL;DR: This Review demonstrates that the exceptional surface (and sometimes bulk) properties of ceria make cerium-based catalysts very effective for a broad range of organic reactions.
Abstract: Ceria has been the subject of thorough investigations, mainly because of its use as an active component of catalytic converters for the treatment of exhaust gases. However, ceria-based catalysts have also been developed for different applications in organic chemistry. The redox and acid-base properties of ceria, either alone or in the presence of transition metals, are important parameters that allow to activate complex organic molecules and to selectively orient their transformation. Pure ceria is used in several organic reactions, such as the dehydration of alcohols, the alkylation of aromatic compounds, ketone formation, and aldolization, and in redox reactions. Ceria-supported metal catalysts allow the hydrogenation of many unsaturated compounds. They can also be used for coupling or ring-opening reactions. Cerium atoms can be added as dopants to catalytic system or impregnated onto zeolites and mesoporous catalyst materials to improve their performances. This Review demonstrates that the exceptional surface (and sometimes bulk) properties of ceria make cerium-based catalysts very effective for a broad range of organic reactions.

324 citations

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TL;DR: In this paper, a series of platinum catalysts supported over various supports (Al2O3, Al 2O3-SiO2 and TiO2) were prepared and characterized by X-ray diffraction, N2 sorption, H2 chemisorption, temperature programmed reduction, FTIR of adsorbed pyridine, 3,3-dimethyl-1-butene isomerization and cyclohexane dehydrogenation.
Abstract: A series of platinum catalysts supported over various supports (Al2O3, Al2O3–SiO2 and TiO2) were prepared and characterized by X-ray diffraction, N2 sorption, H2 chemisorption, temperature programmed reduction, FTIR of adsorbed pyridine, 3,3-dimethyl-1-butene isomerization and cyclohexane dehydrogenation. These catalysts were evaluated for aqueous-phase process (APP) of glycerol at 210 °C, under N2 or H2 atmosphere (60 bar as total pressure). Among the tested catalysts, Pt/TiO2 was the most active and the most selective toward C3 products (propanediols, propanol) which can be further valorized into chemicals. TiO2 was identified as the support leading to the most stable Pt metallic phase, catalytic phase on which the hydrogenation/dehydrogenation reactions take place. The presence of acidic sites brought by the oxide support is necessary for the dehydration reactions (i.e. for C O cleavages), but a too high quantity of these sites can promote the C C bond cleavages via an acidic cracking mechanism. Among the various supported Pt-based catalysts studied in this work, Pt/TiO2 sample appears to be the most promising system for the transformation of polyol in aqueous phase.

65 citations

Journal ArticleDOI
TL;DR: In this article, the transformations of 1,2,3,4-tetrahydroisoquinoline (1234THIQ) and 1234THQ were compared on a sulfided commercial NiMOAl 2 O 3 catalyst in a flow microreactor at 623 K (total pressure: 7 MPa).

47 citations

Journal ArticleDOI
TL;DR: In this paper, the isotope exchange between H2 and D2 was studied at 80°C in a recycling reactor under a pressure of 2 bar in the presence of a sulfided NiMo/Al2O3 catalyst and by means of gas chromatography.

41 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the reactivities in hydrogenation and in isomerization of various olefins on Mo, CoMo and NiMo catalysts in order to evaluate the promoter effect in both reactions.
Abstract: In connection with the specific requirements of the hydrotreating of FCC gasoline, the selectivity of hydrotreating catalysts in hydrodesulfurization with respect to the hydrogenation of olefins has to be controlled and if possible improved. The aim of this study was to compare the reactivities in hydrogenation and in isomerization of various olefins on Mo, CoMo and NiMo catalysts in order to evaluate the promoter effect in both reactions. It was shown that the promotion effect on the hydrogenation of olefins (150 °C, fixed-bed reactor) was depending on their structure. However, the promotion effect of Ni was higher than that of Co whatever the olefin. This is in accordance with the fact that CoMo catalysts are more efficient in the selective hydrodesulfurization of FCC gasoline than NiMo catalysts. The presence of cobalt favours also the skeletal isomerization of the olefins.

37 citations


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Journal ArticleDOI
TL;DR: This review has a wide view on all those aspects related to ceria which promise to produce an important impact on the authors' life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.
Abstract: Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

1,710 citations

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TL;DR: In this article, the authors present the recent technological and theoretical advances related to the CeO2-based nanomaterials, with a focus on the synthesis from one dimensional to mesoporous ceria as well as the properties from defect chemistry to nano-size effects.
Abstract: The controllable synthesis of nanostructured CeO2-based materials is an imperative issue for environment- and energy-related applications. In this review, we present the recent technological and theoretical advances related to the CeO2-based nanomaterials, with a focus on the synthesis from one dimensional to mesoporous ceria as well as the properties from defect chemistry to nano-size effects. Seven extensively studied aspects regarding the applications of nanostructured ceria-based materials are selectively surveyed as well. New experimental approaches have been demonstrated with an atomic scale resolution characterization. Density functional theory (DFT) calculations can provide insight into the rational design of highly reactive catalysts and understanding of the interactions between the noble metal and ceria support. Achieving desired morphologies with designed crystal facets and oxygen vacancy clusters in ceria via controlled synthesis process is quite important for highly active catalysts. Finally, remarks on the challenges and perspectives on this exciting field are proposed.

956 citations

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TL;DR: In this article, the kinetics and mechanism of CO oxidation on single and mixed oxides are examined, alongside the catalyst structures, in a review of the literature on carbon monoxide over oxide catalysts.
Abstract: Oxidation into CO2 is a major solution to CO abatement in air depollution treatments. The development of catalytic converters led to an extraordinary high number of publications on metal catalysts during the last fifty years. Due to the increasing price of noble metals and to remarkable progresses in oxide syntheses, catalytic oxidation of carbon monoxide over oxide catalysts has recently gained in interest, even if some oxides are known to present remarkable activity since the beginning of the 20th century. In this Review, the kinetics and mechanism of CO oxidation on single and mixed oxides are examined, alongside the catalyst structures

821 citations

Journal ArticleDOI
TL;DR: In this article, high aromatic content in diesel fuel has been recognized both to lower the fuel quality and to contribute significantly to the formation of undesired emissions in exhaust gases, and environmental regulations governing the composition of diesel fuels are being tightened in both Europe and the United States.
Abstract: High aromatic content in diesel fuel has been recognized both to lower the fuel quality and to contribute significantly to the formation of undesired emissions in exhaust gases [1, 2]. Because of the health hazards associated with these emissions, environmental regulations governing the composition of diesel fuels are being tightened in both Europe and the United States, leading to limitations on aromatics [3, 4].

750 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated CO oxidation over ceria nanocrystals with defined surface planes (nanoshapes) including rods, cubes, and octahedra, and found that the reducibility of these nanoshapes is in line with their CO oxidation activity.

529 citations