Andréa Maione

Ru/MgO sol-gel prepared catalysts for ammonia synthesis

A new method of preparation of alkali-promoted Ru/MgO catalysts, based on a sol-gel procedure, starting from magnesium ethoxide, Ru3(CO)12 and a cesium compound has been designed. The gels were subjected to an activation/reduction procedure to substantially obtain Ru-CsOH/MgO. The activated catalysts were tested in ammonia synthesis at atmospheric pressure. It was clear that the sol-gel prepared Cs-promoted Ru/MgO catalysts are much more active, under the same reaction conditions, than the analogous catalysts prepared by impregnation procedures.

Structured Pd/γ Al2O3 catalysts on FeCrAlloy fibers for total combustion of methane

Abstract A dip coating method is applied in order to allow the deposition of Pd/γ-Al 2 O 3 on FeCrAlloy-type fibers. All samples are investigated by means of XRD, XPS, CO chemisorption and nitrogen physisorption. The catalytic fibers are tested in the total combustion of methane showing that O 2 /H 2 gaseous pretreatment, which takes place before the catalytic reaction, is strongly beneficial as confirmed by a better dispersion of Pd particles.

Influence of the preparation conditions on the structure of the active phase and catalytic properties of Ni-Co-molybdate propane oxydehydrogenation catalysts

The effect of the pH conditions on the structure and composition of the active phase in Ni0.5Co0.5MoO4 propane oxy-dehydrogenation (ODH) catalyst is investigated by using different characterization techniques: XRD, XPS, laser Raman spectroscopy, chemical composition and BET-surface area. Increasing precipitation pH from 6.0 to 8.5 produces the following effects: i) BET surface area progressively increases, ii) Mo loading decreases, iii) all samples show higher Co loading than Ni in the bulk, iv) the Ni content increases strongly from pH 6.0 to 7.5 and remains almost constant between 7.5-8.5 pH, v) Co content is almost constant in the pH range 6.0-7.5, but strongly increases at pH 8.5, vi) surface composition varies as follows: at pH 6.0: Mo >Co >Ni, at pH 7.5: Mo congruent to Ni > Co, at pH 8.5: Ni > Co congruent to Mo. MoO3 phase was detected only in the sample prepared at pH 6.0. XRD patterns showed, for the catalysts prepared at pH 6.0 and 7.5, diffraction lines characteristics of both beta-NiMoO4 and beta-CoMoO4-like phases. The catalyst prepared at pH 8.5 is a solid solution of beta-NiMoO4 and beta-CoMoO4 in a common molybdate structure and probably NiO and Co3O4 separated phases. Activity measurements conducted at different space-time indicated that the sample prepared at pH 8.5 is the most effective for the propylene production.