Nickel phosphide nanocatalysts for the chemoselective hydrogenation of alkynes

[EN] Well-defined 25 nm nickel phosphide nanoparticles act as a colloidal catalyst for the chemoselective hydrogenation of terminal and internal alkynes. Cis-alkenes are obtained in mild conditions with good conversion and selectivity. The phosphorus inserted in the Ni-P nanoparticles is critical for the selectivity of the nanocatalyst. Mechanistic investigations using isotope labeling provide insight on the reactants interaction with the nanoparticles surface. They pinpoint the occurrence of C-H bond cleavage in terminal alkynes during the reaction. (C) 2012 Elsevier Ltd. All rights reserved.The DGA, the Ecole Polytechnique, the CNRS and the UPMC are acknowledged for financial support.Carenco, S.; Leyva Perez, A.; Concepción Heydorn, P.; Boissiere, C.; Mezailles, N.; Sanchez, C.; Corma Canós, A. (2012). Nickel phosphide nanocatalysts for the chemoselective hydrogenation of alkynes. Nano Today. 7:21-28. doi:10.1016/j.nantod.2011.12.003S2128

The origin of the high electrochemical activity of pseudo-amorphous iridium oxides

The origins of the superior catalytic activity of poorly crystallized Ir-based oxide material for the OER in acid is still under debate. Here, authors synthesize porous IrMo oxides to deconvolute the effect of Ir oxidation state from short-range ordering and show the latter to be a key factor

Method for manufacturing a thin film of ordered silicon nanopatterns

The invention relates to a method for manufacturing a thin film of ordered silicon nanopatterns including the steps of: A) preparing a self-organised reactive nanomask (RNM) consisting of MxM'yOz, referred to as an initial RNM, using an inorganic nanomask INP; B) the liquid deposition of said initial RNM onto a silicon substrate; C) transferring said nanomask MxM'yOz to the silicon substrate by dry etching, by exposing said nanomask MxM'yOz to a fluorinated plasma gas for 0.5 to 4 minutes according to the constitution of said gas, transforming the MxM'yOz into a stable MF2 component referred to as an intermediate nanomask, which enables either a nanoperforated thin film or an ordered lattice of silicon nanowires to be obtained, which have dimensions and a period linked to those of the initial RNM. The invention relates to nanoperforated thin films obtained by the method above, as well as to the use of ordered silicon nanowires for optical and photonic purposes

Hierarchical porosity in silica thin films by a one-step templating strategy using a stimuli-responsive bioderived glycolipid

Hierarchical porosity in thin films obtained with the evaporation induced self-assembly method is a major challenge that is generally accomplished by combining different templating compounds or strategies, each one typical for a given size range. For instance, for small-medium-sized pores (below 20 nm) a library of surfactants exists, while colloids and polymers, as well as phase separation and water condensation strategies, are used for large mesopores to macropores (up to several micrometers). Here, we report the pH-dependent templating effect using a class of entirely bioderived, functional glycolipids obtained from the culture broth of the yeast Starmerella bombicola. We show that these compounds can be used to achieve a micro-to-macro hierarchical porosity in a one-step process by simply tuning the solution pH and without using any additional cosurfactant, cosolvent, or pore-swelling agent. Small-angle X-ray scattering, transmission electron microscopy, scanning electron microscopy, and ellipsoporosimetry data show the multiscale porous texture of silica thin films

Homogeneous Supported Monolayer from Microbial Glycolipid Biosurfactant

International audienceThe development of supported glycosylated lipid layers is an important trend in the field of glyconanomaterials for their interest in understanding sugar-sugar and protein-sugar interactions, these being at the core of cellular, bacterial or viral adhesion. The conventional self-assembled monolayer (SAM) approach generally requires a thiolated glycoconjugate and a gold substrate. In this work, we show how glycolipid amphiphiles of natural origin, commonly known as microbial biosurfactants, can be easily deposited onto a substrate. Spontaneously produced by microorganisms but lacking a thiol group, one can take advantage of their self-assembly properties to prepare homogeneous supported lipid monolayers (SLM). We then choose a saturated glucolipid, G-C18:0, which forms a colloidal lamellar phase under diluted conditions. The lamellae can then be deposited onto a substrate (silicon, gold) using a physical method (dip coating). Dip coating is preferred over more classical deposition methods (Langmuir-Blodgett-LB-, vesicle fusion or spin-coating) because of its versatility, compatibility with aqueous solutions and robust control of the thickness below 10 nm. Defect-free glycosylated SLM from a microbial biosurfactant are then easily developed. A combination of ellipsometry, fluorescence microscopy, atomic force microscopy and infrared nanospectroscopy (AFMIR) show that the glycosylated SLM are defect-free, have a thickness of 2.8 ± 1.0 nm and they are highly homogeneous at scales going from the nm to cm

COMPOSITE MATERIAL COMBINING MOF NANOPARTICLES AND METAL NANOPARTICLES

La présente invention se rapporte à un matériau composite utilisable comme indicateur optique, associant (a) au moins un MOF cristallin poreux, de préférence sous forme de nanoparticules, adapté à l’adsorption de composés organiques volatils , et (b) des nanoparticules de forme anisotrope d’au moins un métal ou alliage de métaux ayant une bande plasmon dans le visible, le métal étant choisi parmi Au, Ag, Cu et Pd ou mélange homogène ou non ou alliage de ceux-ci. L’invention se rapporte également à un procédé de préparation du matériau composite, à un dispositif pour la détection optique de la saturation d’un adsorbant MOF en composés organiques volatils, ainsi qu’à l’utilisation du matériau composite comme indicateur optique pour la saturation d’un adsorbant MOF en composés organiques volatils

POROUS MATERIAL IN THE FORM OF IRIDIUM AND/OR IRIDIUM OXIDE BASED MICROSPHERES, THE PREPARATION METHOD THEREOF AND THE USES THEREOF

The invention relates to a porous material in the form of iridium and/or iridium oxide based microspheres, the preparation method thereof, the use thereof as an anode catalyst in a water electrolyserbased on a solid polymer electrolyte, also called PEM ("Proton Exchange Membrane" or "Polymer Electrolyte Membrane") water electrolyser, or for manufacturing light-emitting diodes for various electronic devices or for motor vehicles, and a PEM water electrolyser comprising such a material as anode catalyst

Periodic nanoporous inorganic patterns directly made by self-ordering of cracks

International audienceSolution-processed inorganic nanoporous films are key components for the vast spectrum of applications ranging from dew harvesting to solar cells. Shaping them into complex architectures required for advanced functionality, often need time-consuming or expensive fabrication. In this work, we show how crack formation is harnessed to pattern porous inorganic films in a single step and without using lithography. We developed aqueous ink formulations that, in the presence of polymeric latexes, enable evaporation-induced, defect-free periodic arrays of cracks with tunable dimensions over several centimeters. The ink formulation strategy was generalized to more than ten inorganic materials including simple and binary porous oxide and metallic films covering a whole spectrum of properties including insulator, photocatalytic, electrocatalytic, conductive or electrochromic materials. Notably, this approach enables three-dimensional self-assembly of cracks by stacking several layers of different compositions, yielding periodic assemblies of polygonal shapes and Janus-type patterns. The crack patterned periodic arrays of nanoporous TiO2 diffract light, and are used as temperature-responsive diffraction grating sensors. More broadly, this method represents a unique example of self-assembly process leading to long-range order (over several cm) in a robust and controlled way