Pectin: A super binder for Silicon-based Li-ion batteries

International audienc

Pectin: A super binder for Silicon-based Li-ion batteries

International audienc

Calix[4]arene-modified silica nanoparticles for the potentiometric detection of iron (III) in aqueous solution

International audienceThis article aims to present the synthesis and the characterization of a novel hybrid material, based on silica nanoparticles, and which can be used as a sensitive element for the electrochemical detection of iron (III). This material was obtained by grafting an iron ligand-based calix[4]arene structure onto nanosized silica particles. The covalent anchoring of the chelator was obtained by nucleophilic coupling reaction between the modified calix[4]arene and the chloropropyl functionalized silica. The grafting reaction was confirmed by FTIR (DRIFT), solid-state 13C Cross-Polarization MAS (CPMAS) NMR and thermal analysis. The interaction between the material and the dissolved iron (III) was demonstrated though potentiometric measurements. A linear evolution of the open circuit potential, which can be used analytically for iron (III) detection, has been obtained

Gold Catalysis and Photoactivation: A Fast and Selective Procedure for the Oxidation of Free Sugars

International audienceA fast and efficient methodology for the selective oxidation of sugars into corresponding sodium aldonates is herein reported. Hydrogen peroxide was used as a cheap oxidant and electron scavenger, in the presence of only 0.003–0.006 mol % of gold in basic conditions. Three photocatalysts were studied, namely Au/Al2O3, Au/TiO2, and Au/CeO2, the latter being the most efficient (TOF > 750 000 h–1) and perfectly selective. Only a 10 min exposition under standard incident sunlight irradiation (A.M.1.5G conditions, 100 mW/cm2) affords total conversion of glucose into the corresponding sodium gluconate. Demonstrating its versatility, this methodology was successfully applied to a variety of oligosaccharides leading to the corresponding aldonates in quantitative yield and high purity (>95%) without any purification step. The photocatalyst was recovered by simple filtration and reused 5 times leading to the same conversion and selectivity after 10 min of illumination