Omar Solorza

Mo-Ru-W chalcogenide electrodes prepared by chemical synthesis and screen printing for fuel cell applications

Abstract We report the results obtained in the characterization of binary W–Se, Ru–Se as well as ternary W–Ru–Se and Mo–Ru–Se electrocatalysts prepared by screen printing and chemical synthesis. The results indicate that Mo–Ru–Se based catalysts prepared by chemical synthesis possess good electrocatalytic activity for oxygen reduction. The final composition of the compound depends on the starting weight percentage of the carbonyl compounds and the post-preparation processing. As-prepared, Mo–Ru–Se was found to be stable in acid medium (H2SO4) with high catalytic activity, but after heat treatment the catalytic activity reduced appreciably due to the loss of Se from the compound.

Characteristics of ZnO:F thin films obtained by chemical spray. Effect of the molarity and the doping concentration

The effect of the zinc acetate molarity combined with the substrate temperatures of ZnO:F thin films deposited by spray pyrolysis, on their physical properties, was studied. The main interest was to optimize the resistivity and the optical transmittance of films deposited at different substrate temperatures. It is to be remarked the influence of the aging of the starting solution on the improvement of the electrical properties of the films. The lowest value of the resistivity was obtained with solutions of 0.2 M. In this case, the resistivity obtained for a film 325-nm thick was 5.5×10−2 Ωcm, decreasing to a value of 6.7×10−3 Ωcm for films 1400-nm thick. Mobility values were approximately 7 cm2/V-S. The transmittance in the visible is near 90% at 550 nm. All the films showed a preferred (002) crystalline orientation irrespective of the deposition conditions. Finally, the grain size increased as the molarity of the solution decreased.

Characterization of co-electrodeposited and selenized CIS (CuInSe2) thin films

Abstract The structural, morphological, compositional and photoelectrochemical properties of co-electrodeposited and selenized CIS thin films were characterized using various techniques. As-deposited as well as selenized films exhibited a compact or a granular morphology depending on the composition. The film stoichiometry was improved after selenization at 550 °C in a tubular furnace. The film conductivity type, carrier concentration and flat-band potential were determined from the photoelectrochemical studies. The films are formed with a mixed composition of the binary as well as the ternary phases. From the results of these studies, a model is suggested for the superficial as well as the bulk conductivity types of the film.

Preparation and characterization of (Zn,Cd)S photoelectrodes for hydrogen production

The authors report the preparation and characterization of (Zn,Cd)S (ZCS) photoelectrodes for hydrogen and oxygen production in a photoelectrolytic cell. ZCS photoelectrodes were prepared by mixing CdS and ZnS powders and sintering at high temperature in the presence of CdCl2, as the flux. In some cases the ZCS was loaded with Mo during the preparation. These mixtures were characterized by structural analysis using X-ray diffraction (XRD), photosensitivity measurements in artificial light (halogen and xenon lamps)in solid state, and in a 0.1 M solution of Na2SO3. The results indicate that a screen printed CdS–ZnS mixture possesses high photosensitivity for its application as photocatalysts for water electrolysis.

Fabrication and testing of a H2-O2 fuel cell using MoxRuySez

Abstract We report the results obtained in the preparation and characterization of Mo x Ru y Se z electrocatalysts for oxygen reduction reaction and the design, construction and characterization of a H 2 –O 2 fuel cell using Mo x Ru y Se z . The catalysts were characterized with respect to their electrocatalytic properties. The fuel cell was designed and built with Mo x Ru y Se z supported on carbon as cathode, Pt supported on carbon as anode, and H 2 SO 4 as the electrolyte. The fuel cell was tested at room temperature and atmospheric pressure. The H 2 –O 2 cell showed an efficiency in the order of 30%.

Characterization of Electrodeposited CuInSe2 Thin Films for Photovoltaic and Photoelectrochemical Applications

Abstract CuInSe2 (CIS) thin films were deposited galvanostatically as well as potentiostatically by an aqueous method. The films were characterized with respect to their structural, opto-electronic and photoelectrochemical properties for application in photovoltaic and photoelectrochemical cells. The film properties depend on parameters like electrode potential, current density, deposition temperature and post-deposition heat treatment. The photoelectrochemical characterization of the film showed that electrodeposited CIS films may be used as photodiodes for hydrogen production by a photocatalytic method. The carrier concentration and flatband potential were determined from C-V measurement, and conductivity type was determined from photoelectrochemical characterization. The annealed films showed NA = 6×l018 cm× and flat band potential VB = 0.15 eV.

Hydrogen energy and fuel cells: A recent R & D program in Mexico

A recent R & D program on hydrogen production, storage and application in fuel cells by employing various physicochemical and biological routes was initiated among the three institutions in Mexico in collaboration with Ecole Polytechnique, Canada. The major theme of this R & D program is hydrogen production using various physicochemical and biological methods, development of high efficiency storage materials and application of hydrogen in fuel cells for production of electricity. The future of the hydrogen energy program in Mexico is reviewed in the light of the high pollution level in several large cities and the energy scenario from 1962 onwards.