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Three series of gallium-containing MFI zeolite were prepared with different gallium content by weight, by hydrothermal synthesis [Ga]-MFI (0.2–4.7 wt% Ga), ion exchange Ga/P (0.5–6.8 wt% Ga) and mechanical mixture Ga+P (0.5–10 wt% Ga). Under hydrogen at 600 °C on the aluminosilicate doped with gallium, a reducing solid ionic exchange occurs between a mobile species (Ga2O) and the protonic sites of the zeolite. The proportion of Ga implied in this exchange depends on both the proximity between Ga2O3 and the zeolite and the initial gallium content. The solid reductive exchange remains limited, ranging from 25% to only a few percent; therefore the gallium species content located in the zeolite micropores is only 0.2–0.4 wt%. The aluminosilicates doped with Ga are more active in both cyclohexane dehydrogenation and propane aromatization than the gallosilicates: the gallium in the framework is much less active than gallium in the exchange position.

Throughout this study, the SiO2, Na2O and H2O contents in the starting gel were modified in order to understand their influence on obtaining pure Y faujasite small crystals. Results were assembled in a ternary phase diagram (SiO2–H2O–Na2O). Furthermore, thorough characterization using multiple structural and physicochemical methods is reported for all the pure faujasite samples, in order to emphasize the effect of H2O, SiO2 and Na2O amounts on their structural (the crystallization rate and the Si/Al molar ratio of the framework) and textural properties (the micropore volume and the crystal size). Good yields in Y faujasite small crystals were obtained when optimizing the starting gel composition compared to the one provided in the literature (typically below 10 wt% of the engaged Si). The results show that the gel domains that are able to give pure Y zeolites are very restricted, making predictions very complicated.

International audience; n order to study the energetic performances of different “pure silica chabazite–LiCl aqueous solution” systems, intrusion–extrusion experiments were performed under high pressure. Depending on the LiCl concentration in the aqueous medium (0 M, 5 M, 10 M, 20 M), an increase of the stored (4.4, 9.9, 13.5, 24.3 J g−1) and restored (2.6, 8.1, 11.8, 20.5 J g−1) energies are observed. Therefore, compared to the “pure silica CHA–H2O” system, the stored energy is increased by 5.5 times for the “pure silica CHA–20 M LiCl” one. The zeolite samples were characterized (XRD, TG, NMR spectroscopy, N2 adsorption and SEM) before and after the intrusion–extrusion process in order to better understand the influence of the LiCl concentration on the system behavior.

International audience; The energetic performances of pure silica ITH-type zeolites were studied by high pressure intrusion–extrusion in water and LiCl aqueous solutions at different concentrations. When pure water was intruded, a bumper behavior was exhibited with an intrusion pressure of 82 MPa and an absorbed energy of 6.6 J g−1. Changing the intruded liquid from water to LiCl aqueous solutions, an increase of the intrusion pressure was observed with 119, 175 and 280 MPa for 5 M, 10 M and 20 M LiCl aqueous solutions, respectively. The energy that the latter system could absorb (30.8 J g−1) was among the highest ever reported. A change in the behavior with LiCl concentration was also observed. The “ITH-type zeosil–20 M LiCl solution” system demonstrated a combination of bumper and shock-absorber behaviors, whereas a bumper behavior was displayed for water and the other LiCl aqueous solutions. All the zeolite samples were characterized before and after intrusion–extrusion experiments (XRD, SEM, N2 adsorption–desorption, TG and NMR analysis) in order to understand the influence of LiCl concentration on the “zeosil–liquid” system behavior.

The impact of crystal size and textural properties of * BEA-type zeolites in the conversion of ethanol-to-hydrocarbons at 350 °C and under 3.0 MPa pressure is investigated. Three * BEA zeolites (molar ratio Si/Al of ca. 23) with important differences concerning their textural properties are synthesized: a material constituted of micron-sized crystals and two hierarchical porous zeolites with a mesoporous network created either by the aggregation of nanometer-sized crystals or by the use of a gemini-type quaternary ammonium surfactant given a nano-sponge zeolite. The micrometric zeolite favors the formation of polyaromatic molecules in same proportion than the concentration of Bronsted acid sites. The deactivation mode of acid sites is poisoning rather than pore blocking. The short thickness of crystal in the nano-sponge zeolite combined with its low acidity, limit the growth of coke molecules as well as their accumulation inside micropores. Coke precursors (alkylbenzenes) are adsorbed on many silanol group located in the ordered mesopores, but the extreme downsizing of the zeolite crystal leads to an unexpected pore blocking by these light molecules.

FAU-type zeolite beads were formed through an shearer/mixer using organic binder (carboxymethylcellulose (CMC)) or inorganic binder (anhydrous sodium metasilicate (Na2SiO3)). Mechanical and adsorption properties of these beads represent necessary characteristics for applications in molecular decontamination. The amount of binder and the size of beads were investigated to determine the optimum conditions to elaborate mechanically stable beads with high adsorption capacities. The size of beads varies from 0.25 mm to 2 mm and the amount of binder was tuned from 5 to 15 wt% of the total bead weight. Nitrogen adsorption–desorption measurements reveal no loss of micropore volume when 5 wt% of binder is used. Adsorption of pollutants were successfully carried out using n-hexane and 1,2-dichlorobenzene as probe molecules. Indeed, FAU-type zeolite adsorbs 26 molecules of n-hexane and 29 molecules of 1,2-dichlorobenzene per unit-cell, whereas the beads prepared with 5 wt% of CMC or Na2SiO3 adsorb about 24 molecules of n-hexane and 25 molecules of 1,2-dichlorobenzene per unit-cell, respectively. The mechanical performances are improved with the addition of only 5 wt% of binder in the mixture. Uniaxial compression tests show that the ultimate compressive strength was multiplied by 4 or 7 when only 5 wt% of CMC or sodium silicate are respectively involved for the conception of 1–2 mm zeolite beads.

International audience; High pressure intrusion–extrusion of concentrated solutions of sodium salts in a pure-silica MFI-type zeolite (Silicalite-1) was studied for potential applications in mechanical energy absorption and storage. It was discovered that the anion nature has a drastic influence on the behavior and the energetic performances of “Silicalite-1 – concentrated Na+X− solution” systems, where X = Cl−, Br−, I−, NO2−, NO3−, ClO4− and CrO42−. In the case of NaNO2, NaClO4, Na2CrO4, and NaI a combination of bumper and shock-absorber behaviors with a partial irreversible solution intrusion was observed, whereas a fully reversible spring behavior is demonstrated for the intrusion–extrusion of NaBr, NaCl and NaNO3 solutions. In comparison with water, the intrusion pressure increases for all the solutions except for NaClO4 one. The irreversibility of intrusion decreases with a dilution rate, and the behavior of the corresponding systems with diluted solutions becomes very close. The variation of the system behavior and intrusion pressure values can be related to a different affinity of the corresponding anions for the pores of Silicalite-1. The samples before and after intrusion–extrusion experiments were characterized using several structural and physicochemical methods (XRD, TGA, solid-state NMR, and N2 physisorption), but no significant structural difference was observed.

International audience; The role of acidity (nature, concentration, strength) and textural properties in the etherification of glycerol with tert-butyl alcohol was studied for a wide range acid catalysts, such as Amberlyst® 15, silica, alumina, silica alumina and four type of zeolite, i.e. FAU, MOR, ∗BEA and MFI. The etherification of glycerol by tert-butyl alcohol is a thermodynamically limited reaction that occurs through a successive reaction sequence and follows an Eley-Rideal type mechanism. We found major evidence that glycerol etherification is not only a function of the amount of Brønsted acid sites, but that it further proceeds via a product shape selectivity mechanism. Indeed, the formation of di-substituted ethers appears at very low conversions for zeolites compared to meso- and macroporous acid catalysts. ∗BEA and MFI zeolites feature similar confining voids and resulting thus in similar intrinsic acid strengths (as proved by n-hexane cracking), but differ in the connectivity (4 vs. 6 channels) and access to these voids (0.54 vs. 0.67 nm), which leads to diffusion issues, notably for the MFI zeolite.

Electron transfers occurring after sorption and photoexcitation of p-terphenyl molecules in the porous void of two MFI type zeolites were investigated. The influence of the morphology and particle size, i.e.; nanosheets and conventional coffin-shaped micron sized crystals (big crystals) on these phenomena were emphasized. The irradiation of PTP occluded in big crystals induces the formation of a radical cation which evolves to an electron-hole pair through the capture of another electron of zeolite. In contrast, if photoexcitation of PTP incorporated in nanosheets induces also radical cation, it is interesting to note that the electron-hole pair formation is not favored in such environment. The absence of charge compartmentalization within nanosheets is put forward to explain the inhibition of electron transfer to create the charge transfer complex. Indeed, the small thickness of nanosheets prevents electron hopping over long distance after ionization and consequently, as the electron is trapped nearby the radical cation, direct recombination is favored.

Conventional syntheses of zeolites generally lead to the formation of crystals whose sizes are of the order of several microns which is not detrimental in a large number of industrial applications. However, the capacity and kinetics of pollutant adsorption which are sensitive to diffusion phenomena, surface and porous volume could potentially be improved by the use of nanocrystal or hierarchical zeolites (micro/mesoporous or micro/macroporous). Indeed, zeosil nanosheets hold great potential because of their small size and their high porous volume that promote access of pollutants and increase the adsorption capacity. Herein, silicalite-1 zeosil with a lamellar morphology was successfully synthesized under hydrothermal conditions (110 degrees C, 10 days) using diquaternary ammonium as structuring agent. Compared to the conventional silicalite-1 material, the porous volume of the synthesized nanosheets determined from the N-2 adsorption-desorption isotherms was found to be multiplied by 3.5 (0.62 cm(3) g(-1)) without altering the microporous volume (0.18 cm(3) g(-1)). This result was also confirmed by the increase of the n- hexane adsorption capacity and kinetics in the silicalite-1 nanosheets compared to the conventional silicalite-1. This approach indicates a new way for obtaining zeosil materials of controlled sizes and shapes for molecular decontamination.

The energetic performances of different “Silicalite-1–LiCl aqueous solution” systems were evaluated under high pressure. Depending on the LiCl concentration in the aqueous medium (0 M, 5 M, 10 M, 20 M), an increase of the intrusion and extrusion pressures and therefore of the stored (∼10, ∼13, ∼19, ∼31 J/g) and restored (∼10, ∼13, ∼18, ∼27 J/g) energies are observed. Thus, compared to the “Silicalite-1–water” system, the stored energy is tripled in the case of “Silicalite-1–LiCl 20 M” system. Several characterizations (XRD, TG, NMR, N2 physisorption, ICP/OES, ...) have been realized before and after intrusion–extrusion experiments in order to reveal the presence or the lack of defects and the possible presence of lithium ions in the material after such experiments. At the short-range order, solid state NMR spectroscopy get evidence of the presence of Q2 and Q3 groups revealing the breaking of some siloxane bridges after the intrusion-extrusion steps and thus the creation of hydroxyl groups set in evidence...

High pressure water and electrolyte solutions intrusion-extrusion experiments in pure-silica *BEA-type zeolite (zeosil β) were performed in order to study the performances of these systems in energy absorption and storage. The "zeosil β-water" system displays a bumper behavior with an intrusion pressure of 53 MPa and an absorbed energy of 8.3 J g(-1). For the "zeosil β-LiCl aqueous solutions" systems the intrusion pressure increases with the LiCl concentration to 95, 111 and 115 MPa for 10, 15 and 20 M solution, respectively. However, for concentrations above 10 M, a transformation of the system behavior from bumper to shock-absorber is observed. The zeolite samples were characterized by several structural and physicochemical methods (XRD, TGA, solid-state NMR, N2 physisorption, ICP-OES) before and after intrusion-extrusion experiments in order to understand the influence of the LiCl concentration on the intrusion-extrusion behavior. It is shown that the intrusion of water and LiCl solutions with low concentration leads to the formation of Si-(OSi)3OH groups, whereas no defects are observed under intrusion of concentrated LiCl solutions. A possible mechanism of LiCl solution intrusion based on separate intrusion of H2O molecules and Li(H2O)x(+) ions is proposed.

Experimental water intrusion–extrusion isotherms were performed at room temperature on two pure silica MTT- and STF-type hydrophobic zeolites (zeosils) with 1D channel and cage pore systems, respectively by applying or releasing a high hydraulic pressure. These zeosils were obtained by hydrothermal synthesis in fluoride medium and characterized by structural and physicochemical methods before and after water intrusion. The system “MTT-type zeosil–water” displays a spring behavior with an intrusion pressure of 176 MPa and a stored energy of 5.3 J g−1. No influence of water intrusion on the structure of MTT-type zeosil was found. The “STF-type zeosil–water” system shows a combination of shock-absorber and bumper behavior in the first cycle with an intrusion pressure of 51 MPa. Nevertheless in the following cycles the system demonstrates a spring behavior with an intrusion pressure of 38 MPa. Such behavior can be explained by the formation of silanol groups under intrusion in some pores confirmed by NMR spectroscopy and TG data.

Molecular modelling is a growing science which allows to calculate short range forces between zeolite frameworks and organic compounds. By using a steric approach, it is possible to design templates matching closely with an inorganic framework. Herein, the design, synthesis and successful application of several di(azacrown ether) templates to direct the formation of FAU- and EMT-type zeolites are reported. Following a high throughput experiment design, the synthesis gel composition was optimized to obtain well-crystallized materials. Taking into account their respective crystallization rates, their textural and morphological properties were comparable to their counterparts, typically structured by 15-crown-5 and 18-crown-6 ethers. This work is the first step toward a further design of structure- and shape-directing templates, in order to control the properties of FAU- and EMT-type zeolites aiming specific catalytic and separation applications.

A bi-layer film composed of a thick layer of ZSM-5 zeolite (MFI-structure type) and a thin layer of EMC-1 zeolite (FAU-structure type) was synthesized on aluminum alloys widely used in aerospace industry. The bottom MFI layer was obtained by direct hydrothermal synthesis while secondary growth method was used for the top FAU layer. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results revealed that both layers are highly crystallized, uniform and well-intergrown with a total film thickness around 10 μm. Nitrogen sorption measurements indicated that ZSM-5 and EMC-1 layers present an accessible porosity. The high micropore volumes lead to considerably good adsorption properties towards pollutants. Such a result was confirmed by the n-hexane sorption capacity of the hybrid film which is identical to what is expected for a corresponding powder mixture. Adhesion of zeolite films on aluminum substrate was investigated by scratch tests which highlighted a good adhesion between the bottom layer and the support as well as between the two zeolite layers. The process described in this paper for the formation of a MFI/FAU bi-layer film can be easily extended to other hybrid coating film.

International audience; A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (＞95%) of iodobenzene with nearly 100 kg iodobenzene converted per kgcat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-*BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structure–activity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized *BEA zeolites and more specifically nanosponge-like *BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-*BEA zeolites.

The effect of surface inorganic−organic interactions on magnetic and structural properties of iron oxide magnetic nanoparticles functionalized by lipophilic stilbene molecules has been investigated. The molecules have been grafted through either phosphonate or carboxylate coupling agents. Mossbauer spectra recorded at 300 and 77K suggest a global composition of Fe2.82O4 for the two types of functionalization. Complementary in-field Mossbauer and SQUID measurements have demonstrated that the nanoparticles consist in a magnetite core surrounded by an oxidized layer. The oxidized shell exhibits a spin canting in the carboxylate case leading to a decrease of the net magnetization of the oxide nanoparticle. No canting occurs in the phosphonate case, and the magnetic properties are therefore preserved. The magnetic properties thus depend on the coupling agent, e.g., surface interactions. This result is of primary importance to tune the magnetic properties of functionalized nanoparticles for biomedical and high ...

The design and the functionalisation of nanoparticles is a promising way to elaborate new functional materials, with combined or coupled properties (magnetic, optical, optoelectronic …). In this context, the direct binding of functional organic conjugated molecules (stilbene derivative) onto the surface of monodisperse Fe 3 O 4 magnetic nanoparticles has been studied. Monodisperse Fe 3 O 4 nanoparticles have been synthesized by adjusting the conditions of precipitation and growth and then stilbene derivatives have been grafted onto the surface of these nanoparticles using either phosphonate or carboxylate groups as coupling agents. The functionalised nanoparticles have been characterized before and after grafting by several techniques (XRD, UV, TEM). Studies have demonstrated that the phosphonate coupling agent allows a higher grafting rate than with the carboxylate coupling agent. The nanoparticles functionalised via carboxylate groups are less stable than those functionalised with phosphonate groups mainly due to a strong P–O–Fe bonding. The coated magnetite nanoparticles retain their intrinsic magnetic properties.

International audience; NEXTLAB 2014-Advances in Innovative Experimental Methodology or Simulation Tools used to Create, Test, Control and Analyse Systems, Materials and Molecules NEXTLAB 2014-Innover dans le domaine de la méthodologie expérimentale et des outils de simulation pour créer, tester, contrôler et analyser des systèmes, matériaux et molécules Abstract — By using a steric approach, it is possible to design templates matching closely with an inorganic framework. Herein, the design, synthesis and successful application of several di(azacrown ether) templates to direct the formation of EMC-1 zeolite (FAU-type) are reported. Following a high throughput experiment design, the synthesis gel composition was optimized to obtain well-crystallized materials. Taking into account their respective crystallization rates, their textural and morphological properties were comparable to their counterparts, typically structured by 15-crown-5 ether. Re´umeútilisation d'agents structuraux originaux pour lasynthè se de zeólithe EMC-1 — En utilisant une approche « ste´ique », il est possible de concevoir des agents structurants qui s'adaptent bien a` la porosite´e la charpente mine´ale. Ici, la conception, lasynthè se et l'application reússie de plusieurs agents structurants de type di(aza-e´her-couronne) pour diriger la formation de zeólithe EMC-1 de type FAU sont reporte´uite a` des synthè ses a` haut-de´it , la composition du gel desynthè se a e´eóptimiseé pour obtenir des mate´iaux bien cristallise´ompte tenu de leurs taux de cristallisation respectifs, leurs proprie´e´exturales et morphologiques sont comparables a` leurs homologues, ge´e´alement synthe´iseén pre´ence du 15-e´her-couronne-5.

International audience; Four pure silica zeolites, chabazite (CHA-structure type) and SSZ-23 (STT-structure type) with cage-like structure and silicalite-1 (MFI-structure type) and beta (⁄BEA-structure type) with channel structure, were synthesized and fully characterized. Their sorption properties were examined using gravimetric method combined with Grand Canonical Monte Carlo simulations (GCMC). Of particular interest is the large difference in the adsorption rates of n-hexane, p-xylene and acetone observed for these zeosils at 25, 75 and 150 C. As expected, in most cases, a decrease in the adsorption capacity is observed with increasing the molar volume of the used probe molecule and the temperature. An exception is observed for the pure silica CHA-type zeolite due to its small pore size which prevents molecules from entering its porosity. However, at higher temperature, the window size widens slightly and allows n-hexane and acetone, which have kinetic diameter close to the pore opening, to enter easily in chabazite. As a result, for this zeosil, an increase in the adsorption capacity compared to that obtained at 25 C is observed. All these zeosils are promising for technological uses in car exhaust gas decontamination.

The grafting of pegylated dendrons on 9(2) nm and 39(5) nm iron oxide nanoparticles in water, through a phosphonate group as coupling agent has been successfully achieved and its mechanism investigated, with a view to produce biocompatible magnetic nano-objects for biomedical applications. Grafting has been demonstrated to occur by interaction of negatively charged phosphonate groups with positively charged groups and hydroxyl at the iron oxide surface. The isoelectric point of the suspension of dendronized iron oxide nanoparticles is shifted towards lower pH as the amount of dendron increases. It reaches 4.7 for the higher grafting rate and for both particle size. Thus, the grafting of molecules using a phosphonate group allows stabilizing electrostatically the suspensions at physiological pH, a prerequisite for biomedical applications. Moreover the grafting step has been shown to preserve the magnetic properties of iron oxide nanoparticles due to super-super exchange interactions through the phosphonate group.

Cassava and tree cassava starch films plasticized with glycerol were produced by casting method. Different glycerol contents (30, 35, 40 and 45 wt. % on starch dry basis) were used and the resulting films were fully characterized. Their water barrier and mechanical properties were compared. While increasing glycerol concentration, moisture content, water solubility, water vapour permeability, tensile strength, percent elongation at break and Young's modulus decreased for both cassava and tree cassava films. Tree cassava films presented better values of water vapour permeability, water solubility and percent elongation at break compared to those of cassava films, regardless of the glycerol content.

Magnetite particles with an average size of 39 nm and good monodispersity have been synthesized by coprecipitation at 70 °C from ferrous Fe2+ and ferric Fe3+ ions by a (N(CH3)4OH) solution, followed by hydrothermal treatment at 250 °C. The magnetite nanoparticles before the hydrothermal step display an average size of 12 nm and are highly oxidized when they are in contact with air. Complementary microstructural and magnetic characterizations of nanoparticles after hydrothermal treatment show unambiguously that they consist of magnetite with only a slight deviation from stoichiometry (δ ≈ 0.05), leading to Fe2.95O4.