A5033212618- Zeolite Catalysis and Synthesis
- Mesoporous Materials and Catalysis
- Catalytic Processes in Materials Science
- Catalysis and Hydrodesulfurization Studies
- Catalysis and Oxidation Reactions
- Chemical Synthesis and Characterization
- Metal-Organic Frameworks: Synthesis and Applications
- Advanced NMR Techniques and Applications
- Catalysis for Biomass Conversion
- Nanomaterials for catalytic reactions
- Catalysts for Methane Reforming
- Crystal Structures and Properties
- Covalent Organic Framework Applications
- Petroleum Processing and Analysis
- NMR spectroscopy and applications
- Analytical Chemistry and Chromatography
- Glass properties and applications
- Electrocatalysts for Energy Conversion
- TiO2 Photocatalysis and Solar Cells
- Biodiesel Production and Applications
- Polyoxometalates: Synthesis and Applications
- Spectroscopy and Chemometric Analyses
- Carbon Dioxide Capture Technologies
- Nanoparticles: synthesis and applications
- Drilling and Well Engineering
Laboratoire Catalyse et Spectrochimie
2015-2024
Normandie Université
2016-2024
Université de Caen Normandie
2015-2024
École Nationale Supérieure d'Ingénieurs de Caen
2014-2024
Centre National de la Recherche Scientifique
2015-2024
École Supérieure d'Ingénieurs en Génie Électrique
2022
Centre de Recherche sur les Ions, les Matériaux et la Photonique
2014
Laboratoire de Physique Corpusculaire de Caen
2014
ETH Zurich
2013
KU Leuven
2013
This review highlights recent developments in the synthesis of nanosized zeolites. The strategies available for their preparation (organic-template assisted, organic-template free, and alternative procedures) are discussed. Major breakthroughs achieved by so-called zeolite crystal engineering encompass items such as mastering using physicochemical properties precursor gel/suspension, optimizing use silicon aluminium sources, rational organic templates structure-directing inorganic cations,...
Abstract The isomerization of o ‐xylene, a prototypical example shape‐selective catalysis by zeolites, was investigated on hierarchical porous ZSM‐5. Extensive intracrystalline mesoporosity in ZSM‐5 introduced controlled silicon leaching with NaOH. In addition to the development secondary porosity, treatment also induced substantial aluminum redistribution, increasing density Lewis acid sites located at external surface crystals. However, strength remaining Brønsted not changed. mesoporous...
The interaction of phenol, anisole, and guaiacol, representatives oxygenate functions present in pyrolysis bio-oils, with oxides such as silica, alumina (pure or doped K F), silica−alumina is investigated by infrared spectroscopy. While phenolic type compounds mainly interact via H-bonding chemisorption their main mode adsorption on alumina. Besides, guaiacol interacts very strongly forming doubly anchored phenates instead monoanchored ones phenol anisole. At temperatures typical...
Five silica samples (four precipitated silicas provided by commercial suppliers and one with the MCM-41 structure) have been studied infrared spectroscopy a homemade thermogravimetry−infrared spectrum (TG-IR) setup. The silanol amount, accessibility to water, different alcohols, affinity water of these various were compared quantified. TG-IR measurements allowed precise determination integrated molar absorption coefficient (ν+δ)OH band, ε(ν+δ)OH = (0.16 ± 0.01) cm μmol−1. It is independent...
Solid state 27Al n.m.r. spectroscopy of various aluminosilicates (zeolites, clays, amorphous SiO2–Al2O3) shows that upon thermal or hydrothermal treatment a line appears at ∼30 p.p.m.; the position this suggests penta-co-ordinated Al is present in all these aluminosilicates.
Chemical etching with fluoride ions is a new approach for secondary porosity engineering of aluminosilicate zeolite frameworks. We show that diluted HF solutions extract preferentially aluminum from The Brønsted acidity ZSM-5 treated in such way decreases, while its structure unaffected after an treatment. With higher concentrations, the number undissociated molecules and concentration HF2– ions, extracting indiscriminately Al Si, increase. addition NH4F shifts chemical equilibria to produce...
Mesoporous ZSM-22 zeolite (TON structure) is prepared by controlled silicon extraction in aqueous NaOH under different conditions of concentration, temperature, and time. The first challenge to synthesize a pure sample, since ZSM-5 cristobalite impurities are hard avoid. For this purpose, hydrothermal syntheses autoclaves 30–1000 cm3 using tumbling or magnetic mixing were conducted. parent (calcined) alkaline-treated samples characterised XRD, AAS, N2 Ar adsorption, TEM, 27Al MAS NMR, FTIR....
Zeolites are widely used in industrial processes, mostly as catalysts or adsorbents. Increasing their micropore volume could further improve already exceptional catalytic and separation performances. We report a tunable extraction of zeolite framework cations (Si, Al) on faujasite-type zeolite, the archetype molecular sieves with cages most catalyst sorbent; this results ca. 10% higher limited impact its thermal stability. This increased from opening some small (sodalite) cages, otherwise...
Last site standing: A new generation of hierarchical Pt/H-ZSM-22 zeolites is designed for the efficient processing upcoming renewable feedstocks. The enhanced accessibility active sites vital superior activity and exceptional selectivity in hydroisomerization model molecules such as nonadecane pristane. As a service to our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized online delivery, but not...
Abstract Zeolites are widely used in many commercial processes, mostly as catalysts or adsorbents. Understanding their intimate structure at the nanoscale is key to control properties and design best materials for ever increasing uses. Herein, we report a new controllable fluoride treatment non‐discriminate extraction of zeolite framework cations. This sheds light on sub‐structure commercially relevant crystals: they segmented along defect zones exposing numerous nanometer‐sized crystalline...
This study reports the seeded synthesis of MFI‐type (ZSM‐5) zeolite in fluoride medium at pH = 8.5. Crystal growth kinetics resulting (ZSM‐5‐F) as a function seed content and crystallization temperature is studied. The time reduced to 1.5 h crystals with sizes below 200 nm Si/Al ratio 23.6 are obtained. A similar characteristics but synthesized hydroxyl (ZSM‐5‐OH) used evaluate ZSM‐5s different media. Their physicochemical properties compared particular attention paid nature, number,...
SAPO-34 crystals are etched in fluoride medium. The interface between crystalline domains is dissolved and yields a hierarchical material with system of straight intersecting mesopores that improve the access to micropore space.
The current energy transition presents many technological challenges, such as the development of highly stable catalysts. Herein, we report a novel "top-down" synthesis approach for preparation single-site Mo-containing nanosized ZSM-5 zeolite which has atomically dispersed framework-molybdenum homogenously distributed through crystals. introduction Mo heals most native point defects in structure resulting an extremely material. important features this are provided by in-depth spectroscopic...
The chemistry of silica-based materials, including zeolites, is strongly influenced by the nature and number their silanols.
Natural gas, the cleanest fossil fuel, is an abundant source of methane and expected to play increasingly important role in powering world's economic growth over energy transition coming decades. Methane has potential be a CO2-free feedstock cogenerate hydrogen (H2) added value "building-blocks" chemicals (e.g., olefins aromatics) for petrochemistry. In this review, two processes (i) oxidative coupling (OCM) production ethylene (ii) nonoxidative dehydroaromatization (MDA) producing benzene...