Entity

Time filter

Source Type


Taibi M.,University of Paris 13 | Jouini N.,University of Paris 13 | Rabu P.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Rabu P.,Fondation ternational Center for Frontier Research in Chemistry | And 2 more authors.
Journal of Materials Chemistry C | Year: 2014

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 Å while the hydroxyacetate interlamellar distance is 10.53 Å. 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 α-type nickel hydroxides, α-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. © 2014 the Partner Organisations. Source


Merkache R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Fechete I.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Maamache M.,Ferhat Abbas University Setif | Bernard M.,CNRS Strasbourg Institute of Chemistry | And 5 more authors.
Applied Catalysis A: General | Year: 2015

The direct hydrothermal synthesis of Fe-KIT-6 mesoporous materials with Ia3d symmetry and high iron loadings is reported for the first time. The Fe-KIT-6 mesoporous materials were characterized by XRD, N2 adsorption/desorption isotherms, SEM, FT-IR, XPS and EPR spectroscopy. The physico-chemical characterization results show that all of the samples have well-ordered cubic mesostructures and that the structural integrity is preserved for nSi/nFe ratios as high as 10. It was found that most of the iron ions exist as isolated framework species, but for Fe-KIT-6 with an nSi/nFe ratio of 10, the presence of extra-framework species/small iron oxide clusters cannot be excluded. The catalytic performances of these materials were tested for carbon dioxide (CO2) hydrogenation and methylcyclopentane (MCP) conversion. The catalytic results show that their catalytic activity increases significantly with increasing iron content. For the MCP conversion, the ring-opening selectivity can be improved by increasing the density of isolated iron atom sites at low reaction temperatures. For the CO2 hydrogenation, the methanation selectivity can be improved by increasing the iron active site density and employing a high reaction temperature. Specifically, the high density of iron sites at high catalyst loadings promotes the methanation reaction at the expense of the RWGS (reverse water gas shift) reaction. Thus, the Fe-KIT-6 materials appear to be suitable catalysts for MCP conversion at low temperatures and CO2 hydrogenation at high temperatures. © 2015 Elsevier B.V. All rights reserved. Source


Merkache R.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Fechete I.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Maamache M.,Ferhat Abbas University Setif | Bernard M.,CNRS Strasbourg Institute of Chemistry | And 5 more authors.
Applied Catalysis A: General | Year: 2015

The direct hydrothermal synthesis of Fe-KIT-6 mesoporous materials with Ia3d symmetry and high iron loadings is reported for the first time. The Fe-KIT-6 mesoporous materials were characterized by XRD, N2 adsorption/desorption isotherms, SEM, FT-IR, XPS and EPR spectroscopy. The physico-chemical characterization results show that all of the samples have well-ordered cubic mesostructures and that the structural integrity is preserved for n Si/n Fe ratios as high as 10. It was found that most of the iron ions exist as isolated framework species, but for Fe-KIT-6 with an n Si/n Fe ratio of 10, the presence of extra-framework species/small iron oxide clusters cannot be excluded. The catalytic performances of these materials were tested for carbon dioxide (CO2) hydrogenation and methylcyclopentane (MCP) conversion. The catalytic results show that their catalytic activity increases significantly with increasing iron content. For the MCP conversion, the ring-opening selectivity can be improved by increasing the density of isolated iron atom sites at low reaction temperatures. For the CO2 hydrogenation, the methanation selectivity can be improved by increasing the iron active site density and employing a high reaction temperature. Specifically, the high density of iron sites at high catalyst loadings promotes the methanation reaction at the expense of the RWGS (reverse water gas shift) reaction. Thus, the Fe-KIT-6 materials appear to be suitable catalysts for MCP conversion at low temperatures and CO2 hydrogenation at high temperatures. © 2015 Elsevier B.V. Source


Palamarciuc O.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Palamarciuc O.,Fondation ternational Center for Frontier Research in Chemistry | Palamarciuc O.,Moldova State University | Delahaye E.,CNRS Institute of Genetics and of Molecular and Cellular Biology | And 5 more authors.
New Journal of Chemistry | Year: 2014

A new method to functionalize layered simple hydroxides by post-synthesis modification is described. A layered cobalt hydroxide was modified with a molecule bearing a free amino group. We show here that it is possible to post-functionalize the metal hydroxide layers by performing in situ microwave assisted reactions with the free amino group, constituting a new appealing strategy for functionalization of layered solids. The obtained compounds are characterized by ancillary techniques and their magnetic properties were investigated, which show that the inorganic magnetic layers are not deeply affected by the post-functionalization process. © 2014 The Partner Organisations. Source


Bourzami R.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Bourzami R.,CNRS Strasbourg Institute of Chemistry | Eyele-Mezui S.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Delahaye E.,CNRS Institute of Genetics and of Molecular and Cellular Biology | And 13 more authors.
Inorganic Chemistry | Year: 2014

A series of new hybrid multilayers has been synthesized by insertion-grafting of transition metal (CuII, CoII, NiII, and ZnII) tetrasulfonato phthalocyanines between layers of CuII and CoII simple hydroxides. The structural and spectroscopic investigations confirm the formation of new layered hybrid materials in which the phthalocyanines act as pillars between the inorganic layers. The magnetic investigations show that all copper hydroxide-based compounds behave similarly, presenting an overall antiferromagnetic behavior with no ordering down to 1.8 K. On the contrary, the cobalt hydroxide-based compounds present a ferrimagnetic ordering around 6 K, regardless of the nature of the metal phthalocyanine between the inorganic layers. The latter observation points to strictly dipolar interactions between the inorganic layers. The amplitude of the dipolar field has been evaluated from X-band and Q-band EPR spectroscopy investigation (Bdipolar ≈ 30 mT). © 2014 American Chemical Society. Source

Discover hidden collaborations