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1.
Souad Mokrane Laïd Makhloufi Nicolas Alonso-Vante 《Journal of Solid State Electrochemistry》2008,12(5):569-574
Conducting polypyrrole (PPy)/C (Vulcan XC-72) composite materials were synthesized by chemical polymerization method. These
materials were used as matrix to support platinum nanoparticles, which were produced by the carbonyl chemical route. For the
same catalyst loading (50 μg cm−2), it was observed that the nature of the composite strongly influences the electrochemical activity of nanoparticulated platinum
toward the oxygen reduction reaction in acid medium. The variation of the PPy/C ratio determines the so-called substrate effect
for electrocatalysis.
Dedicated to Prof. Dr. Teresa Iwasita on the occasion of her 65th birthday in recognition of her numerous contributions to
interfacial electrochemistry. 相似文献
2.
We report in this work new results concerning the temperature dependence of the non-Newtonian viscosity of semi-diluted aqueous micellar solutions of cetyltrimethylammonium bromide (CTAB) in the presence of potassium bromide (KBr). Two structural transitions are responsible for the unusual flow curves obtained. The first transition induced by the shear flow corresponds to an induced liquid crystalline phase of the nematic type; the second corresponds to the disappearing of this phase with increase of the temperature. 相似文献
3.
We report a rheological study on the effect of adding organic salts [sodium tosylate (NaTos) and benzoic acid potassium salt
(BaPs)] on the micellar growth and structure of aqueous solutions of cethyltrimethylammonium chloride (CTAC) at a constant
molar concentration ratio [salt]/[CTAC]. The rheological data show two well-defined domains of growth characterized by scaling
laws for the surfactant concentration. The addition of NaTos leads to an unusual maximum in the viscosity-surfactant concentration
curve. Before the maximum (domain 1), the analysis of the data (η0, τR and G
0) suggests the presence of branched micelles (connections). After the maximum (domain 2), however, the exponents of the scaling
laws do not reflect either the relaxation of this branched structure or that of an entangled transient network structure.
A faster mechanism of relaxation, not yet elucidated governs their dynamics. The exponents of the power laws in the presence
of the BaPs are found, however, to be in accordance with the theory of equilibrium polymers.
Received: 15 April 1998 Accepted in revised form: 20 October 1998 相似文献
4.
S. Mokrane L. Makhloufi H. Hammache B. Saidani 《Journal of Solid State Electrochemistry》2001,5(5):339-347
Conductive polypyrrole (PPy) films and PPy films containing Ge microparticles were synthesized by anodic oxidation of pyrrole
in acidic nitrate solutions using a bare passivated titanium electrode. Well-adhering black PPy films were obtained both under
galvanostatic and potentiodynamic polarization. After the formation of the PPy film, during the first anodic cycle, an increase
of the anodic deposition current with the number of cycles was observed, revealing the increase of conductivity of the growing
film. The variations of the electrode surface area were estimated by impedance spectroscopy measurements. The kinetics of
the PPy film formation is controlled by diffusion of the Py monomer in the solution. The diffusion coefficient, estimated
by two different methods, was ca. 2×10–6 cm2 s–1. The reduction rate of oxygen and protons at the Ti/PPy/Ge electrodes depends on how the Ge microparticles are incorporated
in the PPy film. Optimum conditions for this incorporation are realized with thin PPy films and high Ge loading. Thermogravimetric
analysis shows that the PPy film containing Ge microparticles is more thermally stable than the blank PPy film.
Electronic Publication 相似文献
5.
All reasonable tautomers of 2-hydroxyquinoxaline (2HQ) are investigated by the DFT B3LYP/6-311G(d) method. The optimized geometries corresponding to the minimum energy show that the keto form QX2 is the most stable form. The geometry optimization parameters (bond lengths, bond angles) are compared to the X-ray values. Calculated FTIR, UV, and NMR spectra of QX2 are compared to the experimental data to achieve a synergetic computational and spectroscopic approach for the structure analysis of 2HQ. The electronic properties, frontier molecular orbitals, and Mulliken atomic charges are calculated. 相似文献
6.
L. Benhaddad C. Bazin L. Makhloufi B. Messaoudi F. Pillier K. Rahmouni H. Takenouti 《Journal of Solid State Electrochemistry》2014,18(8):2111-2121
Single-crystalline nanorods and sea urchin-like morphology of the γ-MnO2 nanostructures were successfully synthesized by hydrothermal method at different synthesis durations. The as-synthesized products were characterized by the techniques X-ray powder diffraction (XRD), field emission gun-scanning electron microscope (FEG-SEM) coupled with energy-dispersive X-ray elemental analysis (EDX), transmission electron microscope (TEM), isotherms of N2 adsorption/desorption and BET-BJH models. The effect of synthesis duration on the morphology, porous structure, and crystallographic form of MnO2 powders was studied. The electrochemical reactivity of as-prepared powders was investigated in 1 mol L?1 KOH by both cyclic voltammetry and impedance spectroscopy by using a micro-cavity electrode. The results show that the best electrochemical reactivity of the MnO2 powder was obtained with synthesis duration of 24 h. 相似文献
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9.
Ferhat Hadri Anthony Besq Sylvain Guillou Rachid Makhloufi 《ournal of non Newtonian Fluid Mechanics》2011,166(5-6):326-331
Some additives, like surfactants or polymers, in aqueous solutions lead to dramatic drag reducing effects. Classically the range of concentration of surfactant additive is greater than 500 ppm. It was recently demonstrated that an aqueous solution of CTAC/NaSal (cetyltrimethyl ammonium chloride and sodium salicylate) with a concentration lower than 100 ppm has been found to reduce drag. In this work, the influence of temperature (10–50 °C) and concentration (25–150 ppm) on the drag reduction is studied with an experimental set-up. A cross analysis is made from those results. It reinforces the link between the structure of the micelles (rod-like shape) and the drag reduction rate. 相似文献
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