Size-Dependent Electrocatalytic Activity of Free Gold Nanoparticles for the Glucose Oxidation Reaction.

Understanding the fundamental relationship between the size and the structure of electrode materials is essential to design catalysts and enhance their activity. Therefore, spherical gold nanoparticles (GNSs) with a mean diameter from 4 to 15 nm were synthesized. UV/Vis spectroscopy, transmission electron microscopy, and under-potential deposition of lead (UPDPb ) were used to determine the morphology, size, and surface crystallographic structure of the GNSs. The UPDPb revealed that their crystallographic facets are affected by their size and the growth process. The catalytic properties of these GNSs toward glucose electrooxidation were studied by cyclic voltammetry, taking into account the scan rate and temperature effects. The results clearly show the size-dependent electrocatalytic activity for glucose oxidation reactions that are controlled by diffusion. Small GNSs with an average size of 4.2 nm exhibited high catalytic activity. This drastic increase in activity results from the high specific area and reactivity of the surface electrons induced by their small size. The reaction mechanism was investigated by in situ Fourier transform infrared reflectance spectroscopy. Gluconolactone and gluconate were identified as the intermediate and the final reaction product, respectively, of the glucose electrooxidation.

Electrochemistry as an attractive and effective tool for the synthesis and immobilization of porphyrins on an electrode surface.

Magnesium(II) 10-phenyl-5,15-p-ditolylporphyrin is easily and cleanly transformed by electrolysis. A nitro group is first introduced at the free meso position by anodic substitution. Hydrogenation into the amine is then carried out electrocatalytically under ambient conditions with water as a hydrogen supplier. The synthesized porphyrin under the nickel(II) form can be covalently grafted onto a platinum electrode by electrochemical reduction of the diazonium cation, generated in situ by a reaction of the nickel(II) aminoporphyrin with sodium nitrite and trifluoroacetic acid. The electrosynthesized thin film gives an electrochemical response typical of a porphyrin material. Films grown under our conditions have a maximum surface coverage of approximately 5×10(-10)  mol cm(-2). The modified electrode exhibits a reproducible electrochemical behavior and a good level of stability over potential cycling and exposition to air.

Aromatic nucleophilic substitution (S(N)Ar) of meso-nitroporphyrin with azide and amines as an alternative metal catalyst free synthetic approach to obtain meso-N-substituted porphyrins.

Aromatic nucleophilic substitution reaction of the nitro group of meso-nitroporphyrins with azide and various amines was achieved and represents an alternative procedure to C-N coupling reactions usually needed to obtain such meso-N-substituted porphyrins in good yields.

Magnesium Anthracene System-Based Electrolyte as a Promoter of High Electrochemical Performance Rechargeable Magnesium Batteries.

The development of efficient, inexpensive, and safe rechargeable batteries for large-scale environmentally benign cells is one of the key requirements to accommodate and satisfy various technological applications. To date, the development of magnesium battery as a promising candidate for next-generation battery systems has been hindered by the lack of high performance and stable electrolyte. In this work, we have developed an original, safe, and high-performance class of electrolytes based on a simple mixture of commercially available compounds, that is, Mg(TFSI)2, anthracene, MgCl2, and diglyme solvent. We have proven that anthracene induces stabilization of the reduced form of magnesium involving reversible magnesium plating/stripping with very high current density. The electrolyte investigated exhibits an unprecedented electrochemical stability window of up to 3.1 V, whereas MgCl2 addition allows the improvement of the Mg/electrolyte interface properties and enables a large cyclability of Mg/Mo6S8 Chevrel phase cell, allowing one to reach high performances.

Electrolyte Based on Easily Synthesized, Low Cost Triphenolate-Borohydride Salt for High Performance Mg(TFSI)2-Glyme Rechargeable Magnesium Batteries.

A new class of electrolyte based on TFSI- and triphenolate-borohydride anions was designed and produced which fulfill all requirements of easy synthesis, high ionic conductivity, wide potential window, and noncorrosion of Al current collector. The electrolyte composed of magnesium triphenolate borohydride and Mg(TFSI)2 in glyme simultaneously displays a high conductivity of 5.5 mS cm-1 at 25 °C and a reversible Mg plating/stripping with high current density and Coulombic efficiency at room temperature. By addition of a slight amount of MgCl2 to this electrolyte, a Coulombic efficiency of 90% in an SS/Mg cell, stable cycling performance, and a wide anodic potential of 3.4 V vs Mg2+/Mg on Al current collector can be reached. Reversible and efficient Mg insertion/deinsertion with a high capacity of 94 mAh g-1 and 96% Coulombic efficiency was obtained in a Mo6S8 Chevrel cathode phase.

Chemistry for oncotheranostic gold nanoparticles.

This review presents in a comprehensive ways the chemical methods used to functionalize gold nanoparticles with focus on anti-cancer applications. The review covers the parameters required for the synthesis gold nanoparticles with defined shapes and sizes, method for targeted delivery in tumours, and selected examples of anti-cancers compounds delivered with gold nanoparticles. A short survey of bioassays for oncology based on gold nanoparticles is also presented.