Direct synthesis of mesoporous silica containing cobalt: A new strategy using a cobalt soap as a co-template

A novel approach to incorporate transition metals into porous structures is presented, which makes use of a cobalt soap in combination with the templating agent C16TMABr. An ordered mesoporous silica MCM-41 type material doped with Co is obtained after removal of the organic part by calcination. The a unit cell parameter of the cobalt containing mesoporous matrices is larger than that of pure MCM-41 and increases with the amount of cobalt present in the sample as well as the diameter of the pores. This is not observed when e.g. cobalt acetate is employed instead of the metal soap. The procedure presented establishes a new route for the incorporation of a transition metal into MCM-41 together with a tuning of the porous structure

Recent advances and perspectives for intercalation layered compounds. Part 2: applications in the field of catalysis, environment and health

Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications

Recent advances and perspectives on intercalation layered compounds part 1: design and applications in the field of energy

Herein, initially, we present a general overview of the global financial support for chemistry devoted to materials science, specifically intercalation layered compounds (ILCs). Subsequently, the strategies to synthesise these host structures and the corresponding guest–host hybrid assemblies are exemplified on the basis of some families of materials, including pillared clays (PILCs), porous clay heterostructures (PCHs), zirconium phosphate (ZrP), layered double hydroxides (LDHs), graphite intercalation compounds (GICs), graphene-based materials, and MXenes. Additionally, a non-exhaustive survey on their possible application in the field of energy through electrochemical storage, mostly as electrode materials but also as electrolyte additives, is presented, including lithium technologies based on lithium ion batteries (LIBs), and beyond LiBs with a focus on possible alternatives such XIBs (X = Na (NIB), K (KIB), Al (AIB), Zn (ZIB), and Cl (CIB)), reversible Mg batteries (RMBs), dual-ion batteries (DIBs), Zn-air and Zn-sulphur batteries and supercapacitors as well as their relevance in other fields related to (opto)electronics. This selective panorama should help readers better understand the reason why ILCs are expected to meet the challenge of tomorrow as electrode materials

Tunable synthesis of Prussian Blue in exponentially growing polyelectrolyte multilayer films.

Polyelectrolyte multilayer (PEM) films have become very popular for surface functionalization and the design of functional architectures such as hollow polyelectrolyte capsules. It is known that properties such as permeability to small ionic solutes are strongly dependent on the buildup regime of the PEM films. This permeability can be modified by tuning the ionization degree of the polycations or polyanions, provided the film is made from weak polyelectrolytes. In most previous investigations, this was achieved by playing on the solution pH either during the film buildup or by a postbuildup pH modification. Herein we investigate the functionalization of poly(allylamine hydrochloride)/poly(glutamic acid) (PAH/PGA) multilayers by ferrocyanide and Prussian Blue (PB). We demonstrate that dynamic exchange processes between the film and polyelectrolyte solutions containing one of the component polyelectrolyte allow one to modify its Donnan potential and, as a consequence, the amount of ferrocyanide anions able to be retained in the PAH/PGA film. This ability of the film to be a tunable reservoir of ferrocyanide anions is then used to produce a composite film containing PB particles obtained by a single precipitation reaction with a solution containing Fe(3+) cations in contact with the film. The presence of PB in the PEM films then provides magnetic as well as electrochemical properties to the whole architecture.journal article2009 Dec 15importe

Lamellar nickel hydroxy-halides: anionic exchange synthesis, structural characterization and magnetic behavior:

Nickel-layered hydroxy-halides LHS-Ni-X (X = Cl, Br, and I) have been prepared by exchange reactions conducted in an aqueous medium under an inert atmosphere starting from the parent nickel-layered hydroxyacetate. The latter was prepared by a hydrolysis reaction conducted in a polyol medium. IR and X-ray diffraction (XRD) studies show total exchange. These compounds exhibit a brucite-like structure with a turbostratic nature. Their interlamellar distance varies linearly with the radius of the halide anion in the range 7.9-8.7 angstrom while the hydroxyacetate interlamellar distance is 10.53 angstrom. In comparison with the acetate ion which replaces hydroxyl groups in the brucite-like layer, EXAFS and XRD investigations show that halide ions are intercalated into the interlayer space along with water molecules without any covalent bonding to the nickel ion. All compounds have similar structural features and can be considered as alpha-type nickel hydroxides, alpha-Ni(OH)(2). These compounds exhibit a ferromagnetic character. The latter is discussed on the basis of the Drillon-Panissod model of ferromagnetic layers interacting via dipole interactions and taking into account the structural features established by XANES and XRD studies along with the intrinsic properties of the halide anions

Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry

The synthesis and characterization of six new lanthanide networks [Ln(L)(ox)(H2O)] with Ln = Eu3+, Gd3+, Tb3+ , Dy3+ , Ho3+ and Yb3+ is reported. They were synthesized by solvo-ionothermal reaction of lanthanide nitrate Ln(NO3)(3)center dot xH(2)O with the 1,3-bis(carboxymethyl)imidazolium [HE] ligand and oxalic acid (H(2)ox) in a water/ethanol solution. The crystal structure of these compounds has been solved on single crystals and the magnetic and luminescent properties have been investigated relying on intrinsic properties of the lanthanide ions. The synthetic strategy has been extended to mixed lanthanide networks leading to four isostructural networks of formula [Tb1-xEux(L)(ox)(H2O)] with x = 0.01, 0.03, 0.05 and 0.10. These materials were assessed as luminescent ratiometric thermometers based on the emission intensities of ligand, Tb3+ and Eu3+ . The best sensitivities were obtained using the ratio between the emission intensities of Eu3+ (D-5(0) -> F-7(2) transition) and of the ligand as the thermometric parameter. [Tb0.97Eu0.03 (L)(ox)(H2O)] was found to be one of the best thermometers among lanthanide-bearing coordination polymers and metal-organic frameworks, operative in the physiological range with a maximum sensitivity of 1.38%.K-1 at 340 K

Etude cristallochimique des composes a structure composite incommensurable (LnS)_nNbS_2 (Ln: Yttrium, elements terre-rare)

SIGLEINIST T 73549 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Nanomatériaux, nanotechnologies: quel nanomonde pour le futur?

Chapitre de livreCe chapitre traite de nanomatériaux et de nanostructures, essentiellement artificiels, élaborés et manipulés avec des moyens beaucoup plus compliqués et beaucoup plus lourds que ce que fait la nature

Matériaux hybrides multifonctionnels (Elaboration et propriétés d'hydroxydes lamellaires de métaux de transition magnétiques et luminescents)

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

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