We present some of our research activities dedicated to doped silica-based optical fibers, aiming at understanding the spectral properties of luminescent ions, such as rare-earth and transition metal elements. The influence of the local environment on dopants is extensively studied: energy transfer mechanisms between rare-earth ions, control of the valence state of Chromium ions, effect of the ...

A new nanocomposite catalyst consisting of high-loading cobalt oxide (CoO) on nitrogen-doped reduced graphene oxide (rGO) for oxygen reduction reaction (ORR) was prepared in this work. Its high activity for the ORR in alkaline electrolyte was determined using the rotating disk electrode technique, and further confirmed in real alkaline membrane fuel cells. A combination of physicochemical chara...

Owing to their high energy-conversion efficiency, low or even zero emission, and high energy and power density, fuel cells such as proton-exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) have drawn tremendous attention as potential clean and efficient power sources for both electric vehicles and portable electronics. A major limiting factor of energy-conversion efficie...

Investigation of the solvent and alkoxide precursor effect on the nonhydrolytic sol-gel synthesis of oxide nanoparticles by means of an ether elimination (Bradley) reaction indicates that the best crystallinity of the resulting oxide particles is achieved on application of aprotic ketone solvents, such as acetophenone, and of smallest possible alkoxide groups. The size of the produced primary p...

Superparamagnetism is a phenomenon caused by quantum effects in magnetic nanomaterials. Zero-valent metals with diameters below 5 nm have been suggested as superior alternatives to superparamagnetic metal oxides, having greater superspin magnitudes and lower levels of magnetic disorder. However, synthesis of such nanometals has been hindered by their chemical instability. Here we present a meth...

Nd-doped Si-rich silicon oxide thin films were produced by radio frequency magnetron co-sputtering of three confocal cathodes: Si, SiO2, and Nd2O3, in pure argon plasma at 500oC. The microstructure and optical properties of the films were investigated versus silicon excess and post-deposition annealing treatment by means of ellipsometry and Fourier transform infrared spectrometry as well as by ...

Cobalt Oxide/ Zinc Oxide nanocomposite was synthesized by dropwise addition ofCo(NO)3.6H2O and Zn(NO3)2.4H2O solutions to KOH solution at different temperatures followed bycalcination at 300ºC for 4 h. The morphology and structure of nanoparticles and the influence oftemperature on particle size were studied using scanning electron microscopy (SEM) and X-RayDiffraction (XRD). Minimum particle s...

Copper and copper oxides are well-known excellent catalysts in several chemical processes, but their low mechanical and electrochemical stability restrict their direct utilization as electrodes in electrolytic processes. In this work, the incorporation of copper into cobalt oxide (CuxCo3-xO4) is presented as an excellent approach to obtain highly active and robust copper-based electrocatalysts....

in this research work the solid-solutions of (bi2o3)1-x (co2o3)x, [x= 0.05, 0.1] (1), (bi2o3)1-x (ho2o3) x, [x= 0.025, 0.05] (2), and (bi2o3)1-x-y (co2o3)x (ho2o3)y, [x=0.05] ; [y= 0.01, 0.02] (3) have been synthesized  using sol-gel method. the effects of transition metal oxides doping on the crystallization and phase transition of the bi2o3 were discussed by x-ray diffraction (xrd). the xrd p...