Time filter

Source Type

Aragon-Gonzalez G.,Metropolitan Autonomous University | Leon-Galicia A.,Metropolitan Autonomous University | Gonzalez-Huerta R.,Laboratorio Of Electroquimica Y Corrosion | Camacho J.M.R.,Metropolitan Autonomous University | Uribe-Salazar M.,Metropolitan Autonomous University
Journal of Physics: Conference Series | Year: 2015

A PEM electrolyser for hydrogen production was evaluated. It was fed with water and a 400 mA, 3.5 V cc electrical power source. The electrolyser was built with two acrylic plates to form the anode and the cathode, two meshes to distribute the current, two seals, two gas diffusers and an assembly membrane-electrode. A small commercial neoprene sheet 1.7 mm thin was used to provide for the water deposit in order to avoid the machining of the structure. For the assembly of the proton interchange membrane a thin square 50 mm layer of Nafion 115 was used. © Published under licence by IOP Publishing Ltd.

Oliver-Tolentino M.A.,Laboratorio Of Investigacion En Materiales Porosos | Guzman-Vargas A.,Laboratorio Of Investigacion En Materiales Porosos | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion
ECS Transactions | Year: 2010

The electrochemical response of modified electrode with Cu-ZSM5 deposited on glassy carbon surface has been studied using cyclic voltammetry and open circuit potential (OCP) measurements. The i-E characteristics showed two cathodic processes at c.a. 0.03V and -0.2V/SCE attributed to the formation of Cu+ and Cu0, respectively. The progressive spread of electro active species on the surface of the zeolite was observed by multi sweep cyclic voltammetry experiment. The diffusion of Cu2+ in the ZSM5 layers depends on the cation nature and increases in the order Li +>K+>NH4 +>Na+. The evaluation of reversible behavior indicated that the electrochemical process is affected by adsorption/desorption phenomena at the interface. It was found that the redox processes are proportional to the amount of Cu species in the zeolite structure. ©The Electrochemical Society.

Vazquez-Cuchillo O.,Autonomous University of Nuevo Leon | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion | Zanella R.,National Autonomous University of Mexico | Elizondo-Villareal N.,Autonomous University of Nuevo Leon | Cruz-Lopez A.,Autonomous University of Nuevo Leon
Ultrasonics Sonochemistry | Year: 2013

NaTaO 3 perovskite-like materials were synthesized using sodium acetate and tantalum ethoxide as precursors in an ultrasonic bath at room temperature. The pristine sample was thermally treated at 600 °C and characterized using XRD, N 2 physisorption, DRS, SEM and TEM techniques. The structural characterization by X-ray powder diffraction revealed that the crystallization of the NaTaO 3 phase prepared at 600 °C showed agglomerates sizes in the micrometric scale, as confirmed by scanning electron microscopy (SEM). On the other hand, well-defined NaTaO 3 particles in the nanometric scale were determined using TEM. It was found that, for the treated sample, the band gap and BET area was 3.8 eV and 9.5 m 2 g -1, respectively. The annealed perovskite, deposited onto ITO glass, presented an important variation in the open circuit potential transient during UV light irradiation in neutral solution, compared with its counterpart prepared by solid-state method. These intrinsic properties, given by the preparation route, might be appropriate for increase its photocatalytic activity. © 2012 Elsevier B.V. All rights reserved.

Oliver-Tolentino M.A.,ESIQIE IPN | Guzman-Vargas A.,ESIQIE IPN | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion | Martinez-Ortiz M.J.,ESIQIE IPN | Flores-Moreno J.L.,Metropolitan Autonomous University
Catalysis Today | Year: 2011

In order to evaluate the electrocatalytic properties, Mg/Al and Mg/Ca/Al hydrotalcite-like materials (LDHs) and their corresponding mixed oxide were immersed in a carbon paste electrode matrix to obtain the so-called modified carbon paste electrode (MCPE). Previous to preparation of MCPE, LDH materials were characterized by different techniques, as XRD, FTIR and BET analysis. The electrochemical response of the electrodes was characterized in neutral conditions using reactive blue 69 dye as a probe molecule. Linear sweep voltammetry (LSV), cyclic voltammetry (CV), multi-sweep cyclic voltammetry (MSCV) and open circuit potential transient techniques were employed. Different current magnitudes in the oxygen evolution reaction (OER) were found as a function of thermal treatment and supporting electrolyte (pH). On the other hand, in a solution containing 250 ppm of the probe molecule at neutral pH, peaks attributed to blue 69 oxidation were found at ca. 0.65 and 0.95 V/SCE. The presence of calcium, as additional divalent cation, and the rehydration of the mixed oxide, due to memory effect, have a positive performance, increasing the magnitude of the electrocatalytic process. © 2010 Elsevier B.V. All rights reserved.

Oliver-Tolentino M.A.,Laboratorio Of Investigacion En Materiales Porosos | Guzman-Vargas A.,Laboratorio Of Investigacion En Materiales Porosos | Arce-Estrada E.M.,ESIQIE IPN | Ramirez-Rosales D.,ESFM IPN | And 2 more authors.
Journal of Electroanalytical Chemistry | Year: 2013

In the present work the system Cu-ZSM5 was prepared by aqueous ion-exchange method from zeolite H-ZSM5. The solids were characterized by X-ray diffraction, nitrogen physisorption, temperature-programmed reduction with hydrogen (TPR-H2) and electron paramagnetic resonance (EPR). These porous materials were mixed with poly (methacrylic acid methyl ester) and methyl acrylate (MA), and immobilized on a glassy carbon electrode in order to obtain the so-called zeolite-modified electrode (ZME). The as-prepared electrodes were characterized by infrared spectroscopy and electrochemical techniques as cyclic voltammetry and chronocoulometry. The presence of copper in the zeolite was confirmed by TPR-H2. The XRD results indicate not important structural changes in the zeolite ZSM5 due to copper incorporation. The EPR spectroscopy showed that copper in Cu-ZSM5 is as isolated form of Cu 2+ ions. The results of nitrogen physisorption suggest that the Cu2+ cations are occupying the exchange sites in zeolite ZSM5. On the other hand, the IR spectroscopy revealed the presence of C O and C C groups in the mixture Cu-zeolite/polymer. The electrochemical profiles showed that reduction of Cu2+ to Cu0 occurs by two steps in presence of chloride due to stabilization of Cu+. The influence of anion in the electrolyte suggests that the redox processes Cu2+ to Cu + and Cu+ to Cu0 occurs on the zeolite-modified electrode even at nitrate- and sulfate-based solutions at the glassy carbon/zeolite interface. This stabilization is mainly associated to the interactions between Cu+ and C C group and the zeolite framework acting as "electron reservoir".

Discover hidden collaborations