In this work we intend to increase the distance among the graphite layers, with the purpose of im... more In this work we intend to increase the distance among the graphite layers, with the purpose of improving their physicochemical properties, as for electric co...
MCM-41 SiO 2 and Cu-SiO 2 mesoporous oxides were synthesized by the atrane route with different p... more MCM-41 SiO 2 and Cu-SiO 2 mesoporous oxides were synthesized by the atrane route with different proportions of copper; these materials were impregnated with nickel via wetness incipient. The catalysts obtained were characterized by X-Ray Diffraction, IR, TEM, UV-Vis, BET porosimetry, ICP, and TPR-H 2. Catalytic activity was evaluated in the reforming of ethanol. It has been observed that the generation of a high dispersion of copper oxide facilitates the reduction of the metals. Also, the selectivity of hydrogen increases with the amount of copper in the support; this can be explained due to the influence of copper on the reaction mechanism.
LiFePO4 material was prepared by hydrothermal method at a temperature of 170°C, using Li2CO3, LiA... more LiFePO4 material was prepared by hydrothermal method at a temperature of 170°C, using Li2CO3, LiAc, LiOH as precursors for lithium, and FeSO45H2O and H3PO4 as precursors for Fe and P, the solution pH was set according to the lithium precursor used. The structural characterization was carried by XRD, SEM, TEM techniques. A single crystalline phase was identified and a particle size ranged between 20 and 0.5um was observed for the different lithium precursors. The electrochemical characterization shows a discharge capacity of 130 mAh/g for the LiOH lithium precursor synthetized material.
A new pyrolytic / atrane method for the synthesis of LiCoO 2 and LiMn 2 O 4 is proposed, using at... more A new pyrolytic / atrane method for the synthesis of LiCoO 2 and LiMn 2 O 4 is proposed, using atrane as precursors. The thermal treatment favors the pyrolysis. The products obtained are compared against the commercial solid-solid method. They have a high crystallinity degree and particle micrometric order; in minor size that in solid state reaction. Both materials synthesized show high potential for their application as cathode in Lithium Ion Batteries. ‡ Original Spanish title: Nueva ruta pirolítico/atrano para la síntesis de electrodos catódicos LiCoO2 y LiMn2O4
The existing aspects about synthesis, characterization and electrochemical properties of differen... more The existing aspects about synthesis, characterization and electrochemical properties of different electrodes for lithium ion batteries are analyzed. Identification and synthesis of precursors are included and also the processes of these materials obtaining in Bolivia. The commercial properties for these materials offered by different companies are mentioned. Finally local synthesis of two cathode electrodes (LiMn2O4) and (LiFePO4) from potential precursors present in Bolivia are reported.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, Apr 1, 1994
A kinetic model describing the adsorption of dicyanoaurate and dicyanoargentate ions in activated... more A kinetic model describing the adsorption of dicyanoaurate and dicyanoargentate ions in activated carbon has been derived assuming that the dicyanoions adsorbed onto the external surface are in equilibrium with those in solution. This equilibrium may be described by a modified Langmuir-Hinselwood equation as is usual in heterogeneous catalysis systems. Once adsorbed onto the outer surface, the dicyanoions can diffuse toward the inner surface of the particle through the pores of the carbon, or they can be desorbed back to the liquid phase. The two exit stages are fast enough to maintain the outer surface in a pseudostationary state in normal experimental conditions. Finally, the kinetic parameters for the process are determined. The fitting of the model with experimental data is satisfactory and the range of applications is wide.
In this work we intend to increase the distance among the graphite layers, with the purpose of im... more In this work we intend to increase the distance among the graphite layers, with the purpose of improving their physicochemical properties, as for electric co...
MCM-41 SiO 2 and Cu-SiO 2 mesoporous oxides were synthesized by the atrane route with different p... more MCM-41 SiO 2 and Cu-SiO 2 mesoporous oxides were synthesized by the atrane route with different proportions of copper; these materials were impregnated with nickel via wetness incipient. The catalysts obtained were characterized by X-Ray Diffraction, IR, TEM, UV-Vis, BET porosimetry, ICP, and TPR-H 2. Catalytic activity was evaluated in the reforming of ethanol. It has been observed that the generation of a high dispersion of copper oxide facilitates the reduction of the metals. Also, the selectivity of hydrogen increases with the amount of copper in the support; this can be explained due to the influence of copper on the reaction mechanism.
LiFePO4 material was prepared by hydrothermal method at a temperature of 170°C, using Li2CO3, LiA... more LiFePO4 material was prepared by hydrothermal method at a temperature of 170°C, using Li2CO3, LiAc, LiOH as precursors for lithium, and FeSO45H2O and H3PO4 as precursors for Fe and P, the solution pH was set according to the lithium precursor used. The structural characterization was carried by XRD, SEM, TEM techniques. A single crystalline phase was identified and a particle size ranged between 20 and 0.5um was observed for the different lithium precursors. The electrochemical characterization shows a discharge capacity of 130 mAh/g for the LiOH lithium precursor synthetized material.
A new pyrolytic / atrane method for the synthesis of LiCoO 2 and LiMn 2 O 4 is proposed, using at... more A new pyrolytic / atrane method for the synthesis of LiCoO 2 and LiMn 2 O 4 is proposed, using atrane as precursors. The thermal treatment favors the pyrolysis. The products obtained are compared against the commercial solid-solid method. They have a high crystallinity degree and particle micrometric order; in minor size that in solid state reaction. Both materials synthesized show high potential for their application as cathode in Lithium Ion Batteries. ‡ Original Spanish title: Nueva ruta pirolítico/atrano para la síntesis de electrodos catódicos LiCoO2 y LiMn2O4
The existing aspects about synthesis, characterization and electrochemical properties of differen... more The existing aspects about synthesis, characterization and electrochemical properties of different electrodes for lithium ion batteries are analyzed. Identification and synthesis of precursors are included and also the processes of these materials obtaining in Bolivia. The commercial properties for these materials offered by different companies are mentioned. Finally local synthesis of two cathode electrodes (LiMn2O4) and (LiFePO4) from potential precursors present in Bolivia are reported.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, Apr 1, 1994
A kinetic model describing the adsorption of dicyanoaurate and dicyanoargentate ions in activated... more A kinetic model describing the adsorption of dicyanoaurate and dicyanoargentate ions in activated carbon has been derived assuming that the dicyanoions adsorbed onto the external surface are in equilibrium with those in solution. This equilibrium may be described by a modified Langmuir-Hinselwood equation as is usual in heterogeneous catalysis systems. Once adsorbed onto the outer surface, the dicyanoions can diffuse toward the inner surface of the particle through the pores of the carbon, or they can be desorbed back to the liquid phase. The two exit stages are fast enough to maintain the outer surface in a pseudostationary state in normal experimental conditions. Finally, the kinetic parameters for the process are determined. The fitting of the model with experimental data is satisfactory and the range of applications is wide.
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Papers by Waldo Yapu