Synthesis and structuring of nickel promoted molybdenum sulfide with addition of ionic liquid or amphiphilic water-soluble polymer : application in heterogeneous catalysis

Avec l’épuisement progressif des ressources pétrolières, la production de biocarburant est actuellement en plein développement. Utiliser la biomasse en tant que source d’énergie permettrait également de limiter la concentration en dioxyde de carbone dans l’atmosphère et ainsi l’effet de serre. Cependant son processus de transformation implique une étape d’hydrodésoxygénation qui nécessite d’avoir recours à des catalyseurs de type sulfure de molybdène dopé par du cobalt ou du nickel. Ces catalyseurs sont également indispensables au cours du traitement du pétrole lors du procédé d’hydrodésulfuration qui est primordial pour limiter la pollution de l’air par les gaz de combustion des carburants. Cette thèse propose une méthode de synthèse et de structuration de catalyseurs massiques NiMoS facile à mettre en œuvre et rapide. Deux solvants ont été utilisés : l’eau et le formamide. L’ajout d’un polymère hydrosoluble amphiphile, le PEO113-b-PLLA32, dans l’eau et de liquides ioniques (BMIMNTf2 et BMIMBF4) dans le formamide ont permis la structuration des matériaux et l’obtention de surfaces spécifiques atteignant 55 m2g-1. Ceci représente une surface importante pour ce type de composé, en particulier dans le cadre d’une synthèse par chimie douce. Les premiers tests catalytiques réalisés vis-à-vis de la réaction d’hydrodésoxygénation de l’acide décanoïque montrent une activité catalytique très prometteuse pour ces matériaux.With the progressive decrease of oil resources, the production of biomass fuel is a fast growing field. This could limit the concentration of carbon dioxide in the atmosphere and thus the global warming. The production of this kind of fuel requires the use of catalysts such as nickel or cobalt promoted molybdenum sulfide. These materials are also crucial during the refining of oil, an essential step to limit atmospheric pollution during the classic fuel combustion. New methods to synthesize and structure NiMoS catalysts have been developed in this work. Two solvants have been studied: formamide and water. The addition of an amphiphilic water-soluble polymer (PEO113-b-PLLA32) in water and of ionic liquids (BMIMNTf2 and BMIMBF4) in formamide led to the structuring of the materials with specific surface areas up to 55 m2g-1. This is a high value for this kind of material, especially since the synthesis is carried out under soft conditions. The first catalytic tests dealt with decanoïc acid hydrodesoxygenation and highlighted a promising activity for these material

Microwave Synthesis of a Fluorescent Ruby Powder

International audienceRuby (aluminum oxide doped with Cr) powders were synthesized using a assisted microwave combustion method in an approach developed to involve students in a research-like experiment. The synthesis is fast (5 min) and e fficient. It demonstrates many properties of ruby such as atomic structure, color, and fluorescence as a function of increasing doping content

Synthesis and Structuring of Ni MoS2 by using an Ionic Liquid

International audienceTo minimize air pollution resulting from exhaust gas emission, a decrease in the concentrations of the sulfur compounds in fuels has become a major issue in the last 10 years. The development of catalysts for the hydrodesulfurization process is a challenge for the oil industry. In the present work, a new and easy way to synthesize Ni-Mo-S hydrotreatment catalysts and in particular the effect of ionic liquids on the final structure was studied. It was shown that the addition of the ionic liquid [BMIM][NTf2] to the main reactants [Ni(NO3)2*6H2O and (NH4)2MoS4] had a great impact on the final product morphology. Indeed, formation of nanoparticles instead of gel was observed, and the amount of ionic liquid introduced helped to control the shape and size of the particles. Moreover, it was also highlighted that the presence of an ionic liquid favored the promotion of MoS2 with Ni with an optimal Ni/(Ni+Mo) atomic ratio of 0.3, and it also impacted the nanostructure, leading to thinner and shorter MoS2 slabs, which are two attractive points for catalytic applications

Synthesizing and Playing with Magnetic Nanoparticles: A Comprehensive Approach to Amazing Magnetic Materials

International audienc

Synthesizing and Playing with Magnetic Nanoparticles: A Comprehensive Approach to Amazing Magnetic Materials

International audienc

Effect of the presence of ionic liquid during the NiMoS bulk preparation in the transformation of decanoic acid

International audienceThe impact of the presence and amount of [BMIM][NTf2] ionic liquid during the preparation of bulk NiMoS catalysts was investigated. It was clearly shown that these factors have a strong influence on both the morphology and specific surface area of the obtained NiMoS samples. Most interestingly the catalytic activity for the transformation of decanoic acid increased up to three times when IL was present during synthesis. In the same time, a greater selectivity towards hydrocarbons was observed. On the whole a clear relationship between catalytic activity, selectivity and NiMoS morphology was demonstrated. Consequently, it is possible to modify the morphology of the materials and impact the catalytic properties by changing the synthesis conditions