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Portales-Martinez B.,Research Center e Innovacion Tecnologica del | Gonzalez-Huerta R.G.,Laboratorio Of Electrocatalisis | Dominguez-Esquivel J.M.,Mexican Institute of Petroleum | Cortes-Escobedo C.A.,Research Center e Innovacion Tecnologica del
Journal of New Materials for Electrochemical Systems | Year: 2012

The electrochemical capacitance for a double layer of ordered mesoporous carbon (OMC) nanofibers functionalized under differing conditions is presented. OMC nanofibers were prepared using the molding method from SBA-15 and sucrose. Functionalisation was performed using varying HNO 3 concentrations at 110°C and 120°C assisted by microwave radiation over 3 minutes. The transmission electron micrographs of the resulting fibers are reported. The capacitance, surface area and functional groups as functions of the acidity and heat treatment were analysed via cyclic voltammetry, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy, respectively. Ordered nanofibers treated with 7.7 M HNO 3 at 110°C exhibited the highest capacitance. © J. New Mat. Electrochem. Systems. Source


Ruiz-Camacho B.,Polytechnic University of Guanajuato | Martinez-Gonzalez J.H.,Polytechnic University of Guanajuato | Gonzalez-Huerta R.G.,Laboratorio Of Electrocatalisis | Tufino-Velazquez M.,Laboratorio Of Fisica Avanzada
International Journal of Hydrogen Energy | Year: 2014

The electrochemical activity and thermal stability of the Pt/TiO2-C were evaluated in the oxygen reduction reaction (ORR) in acid medium at different temperatures. The platinum was selectively deposited onto the TiO2 (Ebg = 2.3 eV) by the photo-irradiation of platinum precursor (Pt4+→Pt0). The Pt/TiO2-C electrocatalyst prepared was characterized by XRD, TEM/EDS, cyclic and lineal voltammetry techniques. TEM images indicated that platinum nanoparticles (<5 nm) were deposited in agglomerates form around the oxide sites. EDS and XRD results confirm the composition and crystalline structure of Pt/TiO2-C. The thermal stability and electrochemical activity of the Pt/TiO2-C for ORR at different temperatures (298-343 K) is higher than Pt/C commercial sample (Pt-Etek). A more favorable apparent enthalpy of activation for Pt/TiO2-C was greatly influenced by addition of oxide in the catalyst compare to Pt-Etek. Single H2/O2 fuel cell performance results of Pt/TiO2-C show an improvement of the power density with the increase of the temperature. © 2014 Hydrogen Energy Publications, LLC. Source


Tamayo-Meza P.,National Polytechnic Institute of Mexico | Ovchinsky A.S.,Institute Metalurgia | Sandoval-Pineda J.M.,National Polytechnic Institute of Mexico | Flores-Herrera L.A.,National Polytechnic Institute of Mexico | And 2 more authors.
Revista Facultad de Ingenieria | Year: 2014

With the construction of a plane model, a qualitative study was made in order to observe the transactions that are developed during the fracture process and its simulation on different sections of a composite, from the accumulation of the damage stage to the moment when the crack propagates abruptly causing a macro fracture. An algorithm was developed to observe the stress redistribution processes and the compound is simulated including packaging defects of the filaments. During the study of the fracture processes in reinforced composites there are many factors to consider that are interrelated and that have a casual character. The mechanical properties of the fibers and the matrix, the matrix-fiber adherence and the resistance of the interface, all vary with the application of the load. The use of computational methods opens great possibilities for the development of the simulation and the models of the fracture processes. Source


Corona-Guinto J.L.,ESIME IPN UA | Cardeno-Garcia L.,Laboratorio Of Electrocatalisis | Martinez-Casillas D.C.,CINVESTAV | Sandoval-Pineda J.M.,ESIME IPN UA | And 3 more authors.
International Journal of Hydrogen Energy | Year: 2013

The Proton Exchange Membrane Water Electrolyzer (PEMWE) can be coupled to renewable energy sources (solar radiation and wave energy), which produce the necessary electricity for splitting the water. In this work the performance of a PEMWE using RuIrCoOx as anodic electrocatalyst had been examined. The oxide powder was synthesized using a chemical reduction method, followed by thermal oxidation. The electrochemical properties of the electrocatalysts were examined by cyclical and lineal voltammetry in 0.5 M H2SO 4. It was found that RuIrCoOx oxide electrodes present a stable performance for OER. The PEMWE was designed and in-home built. Chrono-potentiometric experiments were recorded in the current range of 0.25 mA cm-2 to 75 mA cm-2 at 300 s. The current pulses length is chosen to be sufficiently long so that the voltage remains constant. Their intrinsic electrocatalytic activity in combination with their large surface area and stability are quite promising for the development of economically feasible electrocatalysts for (PEMWE). Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

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