Preparation and characterization of palladium – chromium catalysts generated from mixed salts

Palladium chromate and dichromate have been synthetized and characterized by X-ray diffraction and EXAFS. These compounds were reduced between 200 and 600° C in flowing hydrogen. Below 400° C, 20 A Pd particles supported on amorphous chromium oxide are observed. Above this temperature, EXAFS shows that a bimetallic compound is formed corresponding to the composition Pd88Cr12

An exafs and volumetric study of the formation of hydrides on Pd particles encaged in Y-zeolite

EXAFS performed on 10 Å particles of Pd in the network of a Y-zeolite has shown that in vacuum the structure of the metal is similar to that of the bulk.The lattice expansion observed on the EXAFS data when 500 mbar H2 is introduced, is slightly smaller than what is observed on the bulk upon the formation of the β-hydride.It is inferred that on small clusters, where the number of sites is reduced, the stoichiometry of the hydride is reduced to 0.4 H/Pd instead of 0.6

Role of chromium in the stability of Ni/Al2O3 catalysts for natural gas reforming

Ni/Al2 O3 and Ni–Cr/Al2O3 catalysts prepared with melt salts of Ni and Al (Al/Ni=0.5) were studied by magnetic measurements, electron microscopy and catalytic properties. An increase in the catalytic activity and stability during partial oxidation of methane and CO reforming reactions at 973 K was produced by the chromium addition. The Ni–Cr alloy was 2 formed by reduction at high temperature 1073 K , producing a dilution effect of Ni crystal and modifying the basicity of the support. Both effects would inhibit the catalyst deactivation increasing the useful life and stability of the nickel.Fil: Gónzalez, María Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Nichio, Nora Nancy. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Moraweck, B.. Institut de Recherches sur la Catalyse; FranciaFil: Martin, G.. Institut de Recherches sur la Catalyse; Franci