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Dabaki Y. Boussami S. Khaldi C. Takenouti H. ElKedim O. Fenineche N. Lamloumi J. 《Journal of Solid State Electrochemistry》2017,21(4):1157-1164
Journal of Solid State Electrochemistry - The studied electrochemical properties of the LaNi3.55Mn0.4Al0.3Co0.2Fe0.55 alloy showed a rather poor performance. To improve them, ZnO, a doping agent at... 相似文献
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Gabrielli C Keddam M Portail N Rousseau P Takenouti H Vivier V 《The journal of physical chemistry. B》2006,110(41):20478-20485
Electrochemical impedance spectroscopy experiments were performed on a microdisk electrode in a thin-layer cell using a scanning electrochemical microscope for controlling the cell geometry. Experimental data showed that when the thin-layer thickness diminished, an additional low-frequency response appeared. It was ascribed to the radial diffusion of the electroactive species and was strongly dependent on the thin-layer dimensions (both thickness and diameter). Moreover, the numerical simulation of the impedance diagrams by finite element method calculations confirmed this behavior. An equivalent circuit based on a Randles-type circuit was proposed. Thus, the diffusion was described by introducing two electrical elements: one for the spherical diffusion and the other for the radial contribution. A nonlinear Simplex algorithm was used, and this circuit was shown to fit the impedance diagrams with a good accuracy. 相似文献
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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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L. Robbiola K. Rahmouni C. Chiavari C. Martini D. Prandstraller A. Texier H. Takenouti P. Vermaut 《Applied Physics A: Materials Science & Processing》2008,92(1):161-169
The present study concerns the chemical–physical and electrochemical characterisations of the pale green surfaces formed on
outdoor bronzes exposed in urban conditions. In the first part, results from investigations performed on the equestrian statue
of the French king Louis XIV exposed in the Palace of Versailles (France) are given. Analyses by energy-dispersive spectrometry
and Raman spectroscopy, coupled with scanning electron microscopy, show that the external layer is characterised by a marked
selective dissolution of copper and zinc of the alloy leading to an important relative enrichment in tin compounds. The same
phenomenon with the same magnitude, determined from dissolution factors fCu and fZn, has also been evidenced on other bronze monuments used for comparison. Proportionality between the amount of dissolved copper
and zinc cations to their respective initial content in the alloy is evidenced independently of the tin content. The pale
green patina appears to be a complex mixture of copper and tin compounds whose structure still needs to be more precisely
characterised. In the second part, the electrochemical reactivity of tin compound enriched patina was investigated by cyclic
voltammetry from a Cu10Sn electrode in sulfate solution at pH=2 and 5.6. This patina is stable at pH 5.6 but reactive at pH
2 in relation to the modification of properties of tin species in the patina. Mott–Schottky application in pH 5.6 solution
revealed that the bronze patina exhibits two types of semiconducting properties according to the potential domains, similar
to what has been observed for pure tin in aqueous solutions. The destabilisation of bronze patinas in outdoor conditions and
consequently the cyclic erosion due to rainfall have been attributed to the modification of tin species properties rather
than to the transformation of copper compounds.
PACS 07.78.+s; 81.05.-t; 81.15.-z; 81.65.Kn 相似文献
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Farid Nâamoune Bouzid Messaoudi Abdelkrim Kahoul Nabila Cherchour Alain Pailleret Hisasi Takenouti 《Ionics》2012,18(4):365-370
In this investigation, Mn3O4 spinel-type oxide was synthesized at low temperature using the Pechini process. We employed a sol-gel route, in which a solution
of Mn(II) in a mixture of citric acid and ethylene glycol was heated to form a polymeric precursor, followed by annealing
at lower temperature. The oxide obtained was identified by X-ray diffraction, scanning electron spectroscopy, and Raman spectroscopy.
The results revealed that the formation of Mn3O4 hausmannite structure with a minor secondary phase of MnSO4 occurred at or above 280 °C. The sample powder consisted of fine grains with homogeneous morphology and an average size close
to 1 μm was obtained. This new preparation procedure yielded an electrode oxide which appears to be a promising cathode material
for fuel cells and metal-air batteries. 相似文献
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Yassine Ben Belgacem Chokri Khaldi Jilani Lamloumi Hisasi Takenouti 《Journal of Solid State Electrochemistry》2016,20(7):1949-1959
For the purpose of lowering the cost of metal hydride electrode, the La of LaY2Ni9 electrode was replaced by Ce. The electrochemical performances of the CeY2Ni9 negative electrode, at a room and different temperatures, were compared with the parent alloy LaY2Ni9. At room temperature during a long cycling, the evolution of the electrochemical capacity—the diffusivity indicator (\( \frac{D_{\mathrm{H}}}{a^2} \))—the exchange current density, and the equilibrium potential were determined. At different temperatures, the electrochemical characterization of this alloy allowed the estimation of the enthalpy, the entropy, and the activation energy of the hydride formation. The evolution of the high-rate dischargeability was also evaluated at different temperatures. Compared with the parent LaY2Ni9 alloy, CeY2Ni9 exhibits an easy activation and good reaction reversibility. This alloy also conserves a good lifetime during a long-term cycling. A lower activation energy determined for this alloy corresponds to an easy absorption of hydrogen into this new alloy. 相似文献
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