Laboratorio Of Procesos Cataliticos

Buenos Aires, Argentina

Laboratorio Of Procesos Cataliticos

Buenos Aires, Argentina
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Poggio Fraccari E.,Laboratorio Of Procesos Cataliticos | D'Alessandro O.,CONICET | Sambeth J.,CONICET | Baronetti G.,Laboratorio Of Procesos Cataliticos | Marino F.,Laboratorio Of Procesos Cataliticos
Fuel Processing Technology | Year: 2014

Cerium-manganese mixed oxides with different composition were prepared by co-precipitation, characterized and evaluated for the water-gas shift (WGS) reaction. Base metal (5 wt.% Cu and 5 wt.% Ni) catalysts supported on Ce-Mn mixed oxides were also tested for the WGS reaction. The activity of the bare supports is higher in the mixed samples than in pure ceria or manganese oxide. This result can be explained by a combination of greater reducibility and surface area in the mixed samples. Addition of base metals produces superior WGS catalysts. Particularly, nickel catalysts tested are able to reduce typical CO concentrations entering the WGS process to the CO levels tolerated by phosphoric acid fuel cells in a single unit operated at 400 C. © 2013 Elsevier B.V.


Romero A.,Laboratorio Of Procesos Cataliticos | Jobbagy M.,University of Buenos Aires | Laborde M.,Laboratorio Of Procesos Cataliticos | Baronetti G.,Laboratorio Of Procesos Cataliticos | Amadeo N.,Laboratorio Of Procesos Cataliticos
Catalysis Today | Year: 2010

The effect of the Ni(II)-Mg(II)-Al(III) layered double hydroxide (LDH) activation conditions over the surface and bulk composition and the catalytic performance in ethanol steam reforming (ESR) is studied. Ternary oxides were prepared by thermal decomposition of LDHs synthesized using the homogeneous precipitation method with urea. Catalyst precursor is submitted to two different activation treatments: calcinations at 400, 500, 600 and 700 °C with subsequent reduction at 720 °C, or direct reduction at 720 °C. The samples were characterized by sorptometry, H2 chemisorption, ICP chemical analysis, thermogravimetric analysis, X-ray diffraction, X-ray photoelectronic spectroscopy and temperature programming reduction. The catalysts obtained by calcination at 600 °C and then reduction at 720 °C and those directly reduced at 720 °C showed the better performance in ESR. The precursor submitted to a proper thermal treatment develops, through a decoration-demixing process, a Ni(II)-poor spinel-type shell onto NiO domains.


Milberg H.,Laboratorio Of Procesos Cataliticos | Juan A.,National University of the South | Amadeo N.,Laboratorio Of Procesos Cataliticos | Irigoyen B.,Laboratorio Of Procesos Cataliticos
Journal of Molecular Catalysis A: Chemical | Year: 2010

In this work, we performed density functional theory (DFT) calculations to study carbon adsorption on the Ni(1 0 0) surface and absorption in the bulk of nickel-based catalysts. The ideal catalyst surface was modeled as a five-layer Ni(1 0 0) slab. We also studied the influence of magnesium, considered as an atomic substitutional impurity, on carbon adsorption and migration into the bulk. To study the effect of Mg on the structure of Ni-based catalysts, we replaced a Ni atom by a Mg atom, on the surface and also in the bulk. Then, we relaxed the Mg and Ni positions. Our results showed that Ni atoms were pushed away from Mg. We also performed energy calculations to evaluate carbon interactions on different preferential sites of the Ni-slab, and also the effect of Mg atom on these deposition processes. The calculations showed that carbon adsorption on the bare Ni(1 0 0) surface was more favorable than deposition on this surface doped with magnesium. Our results also indicated that Mg could improve the interaction of surface-adsorbed carbon with gas phase oxygen, leading to the formation of a CO precursor species. In this way, magnesium promotes Ni-based catalysts hindering the surface from attaining a high carbon coverage, and thus making difficult the formation of carbon agglomerates and carbon whiskers. We also considered the effect of Ca in the C-O interaction on the metal surface. © 2009 Elsevier B.V. All rights reserved.


Romero A.,Laboratorio Of Procesos Cataliticos | Jobbagy M.,Argentinean Institute of Chemical Physics for Materials, Environment and Energy | Laborde M.,Laboratorio Of Procesos Cataliticos | Baronetti G.,Laboratorio Of Procesos Cataliticos | Amadeo N.,Laboratorio Of Procesos Cataliticos
Applied Catalysis A: General | Year: 2014

The Ni(II)Mg(II)Al(III) LDH were obtained by homogeneous precipitation urea method, after a proper thermal treatment resulted in an active catalyst for the ethanol steam reforming. After catalytic performance, catalysts were analyzed by temperature programmed oxidation (TPO), in order to quantify carbon deposits. Reduced Ni area was evaluated by H2 static volumetric chemisorption measurements in a Micromeritics AutoChem II 2920 equipment. Thermogravimetric studies were carried out in a Shimadzu TGA-51H equipment, using a heating ramp of 10 K/min in air flow of 50 cm3/min. Experimental equipment used for catalytic evaluation consists of a quartz tubular reactor heated in electric oven at the reaction temperature, which is monitored by a thermocouple placed inside the reactor. The vaporized current is diluted with argon at the entrance of the reactor. It can be observed PXRD spectra of precursors with different Mg content, all samples show characteristic signals of LDH.


Dieuzeide M.L.,Laboratorio Of Procesos Cataliticos | Iannibelli V.,Laboratorio Of Procesos Cataliticos | Jobbagy M.,Argentinean Institute of Chemical Physics for Materials, Environment and Energy | Amadeo N.,Laboratorio Of Procesos Cataliticos
International Journal of Hydrogen Energy | Year: 2012

The aim of this work is to study the catalytic activity of Ni(10%) based catalysts supported over ã-Al 2O 3 modified with Mg (3%) for the steam reforming of glycerol. Catalysts have been prepared by incipient wetness impregnation method; analysing the effect of the calcination temperature of the modified support and the calcination temperature of the catalysts. Catalysts were characterized by temperature programmed reduction, (TPR), x-ray diffraction (DRX) and BET surface area. All catalysts were tested for this reaction in a fixed bed reactor. The best performance was achieved with the catalyst calcined at 500 °C being the optimum calcination temperature for the modified support of 900 °C This behaviour is ascribable to the formation of MgAl 2O 4 spinel which favours the dispersion of Ni°, responsible of the catalytic activity. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Zimicz M.G.,CONICET | Larrondo S.A.,CONICET | Larrondo S.A.,Laboratorio Of Procesos Cataliticos | Prado R.J.,Federal University of Mato Grosso | And 2 more authors.
International Journal of Hydrogen Energy | Year: 2012

The aim of this paper is to gain further insight in the reduction and reoxidation processes taking place when Ce 0.9Zr 0.1O 2 mixed oxides are in reducing or oxidizing atmospheres, respectively. The reduction process of these mixed oxides synthesized by two stoichiometric nitrate-aminoacid gel-combustion routes using glycine and lysine as fuels is studied by conventional H 2-Temperature Programmed Reduction experiments. The results are compared with those obtained by time-resolved in situ X-ray absorption near-edge spectroscopy (XANES) in the energy level corresponding to the Ce L III absorption edge. The reoxidation process by this last technique is also studied. Even though the identical composition and crystal structure of both samples, the redox processes resulted very different for each solid, suggesting the influence of specific surface area, pore volume and particle size on them. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Diaz-Rey M.R.,University of Malaga | Cortes-Reyes M.,University of Malaga | Herrera C.,University of Malaga | Larrubia M.A.,University of Malaga | And 3 more authors.
Catalysis Today | Year: 2015

H2 rich gas produced from Scenedesmus almeriensis biomass residue after lipidic extraction by low temperature catalytic gasification is addressed. The pyrolysis-gasification behavior under different atmospheres (CO2/He, H2O/He and CO2 + H2O/He) were investigated using thermal gravimetric analysis. The conversion of the biomass takes place into three stages, according to its composition and corresponding to: loose of water bonded (30-200°C), major pyrolysis involving devolatilization (200-500°C) and decomposition of bio-char produced (500-800°C). The calculated apparent activation energy for the main pyrolysis stage was 97 kJ mol-1. Ni-based supported alumina catalysts (Ni, Ni-Pt and Ni-Rh) were prepared by impregnation. The catalyst influence on the final gas composition as well as in its HHV determined in mixed CO2 + H2O/He gasification carried out in a double fixed bed reactor configuration with the catalyst located in the second bed upstream. Parallel and secondary reactions as reforming of tar and char together with WGS and Boudouard also take place favoring gas fraction yield with a value close to 0.3 Nm3 of gas per kg of biomass. The catalytic role of Ni-Pt/Al2O3 catalyst in further reforming of the gas resulting from the gasification improves H2 content even at low temperature interval (600-700°C). © 2014 Elsevier B.V. All rights reserved.


Poggio E.,Laboratorio Of Procesos Cataliticos | Jobbagy M.,Argentinean Institute of Chemical Physics for Materials, Environment and Energy | Moreno M.,Laboratorio Of Procesos Cataliticos | Laborde M.,Laboratorio Of Procesos Cataliticos | And 2 more authors.
International Journal of Hydrogen Energy | Year: 2011

A high yield green method was developed for the preparation of reactive nanotextured ceria (CeO2). The preparation method is based on the oxidation of a crystalline Ce(OH)CO3 precursor that decompose at relative low temperature (ca. 250 °C) yielding CeO2 nanocrystals initially rich in Ce3+. After increasing calcination temperatures (in the range 350-650 °C), PXRD analysis show a slight crystal growth after calcination temperatures up to 550 °C, however cell contraction in such case denotes the definitive oxidation of remnant Ce3+ centers. XPS results confirm Ce3+ fraction diminution as calcination temperature increases. TPR profiles of ceria samples show two reduction events being the low temperature one (at ca. 500 °C) related to a surface process in which approximately only one cerium monolayer is involved. Catalytic activity tests for COPROX reaction were performed under differential reactor conditions to evaluate their activity in the temperature range 100-300 °C. The optimum activity recorded for the sample calcined at 450 °C accounts for the compromise between oxide's activation and surface preservation. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Graschinsky C.,Laboratorio Of Procesos Cataliticos | Laborde M.,Laboratorio Of Procesos Cataliticos | Amadeo N.,Laboratorio Of Procesos Cataliticos | Le Valant A.,University of Poitiers | And 3 more authors.
Industrial and Engineering Chemistry Research | Year: 2010

A kinetic study of ethanol steam-reforming reaction on Rh catalyst supported over a spinel structure (MgAl2O4/Al 2O3) was carried out. From the analysis of products distribution, the following four reactions were proposed as the reaction scheme: C2H5OH → CO + CH4 + H2 (ED), C2H5OH + H2O → CO2 + CH 4 + 2H2 (ER), water-gas shift reaction, and methane steam-reforming reaction. When the initial rate method was applied, it was demonstrated that in the rate-determining step (RDS) two active sites of the same type are involved. With use of our experimental results and data obtained from the literature, a sequence of 14 elementary steps were proposed, in agreement with the reaction scheme. Taking into account both the reaction mechanism and the occurrence of two active sites in the RDS, four different kinetic expressions can be formulated in which the RDS is (1) dissociative adsorption of ethanol, (2) dehydrogenation of ethoxide, (3) C-C bond scission, or (4) reaction between two adsorbed species. Finally, when discrimination models were applied, it was verified that the mechanism that fits experimental data is that in which the RDS is the surface reaction. © 2010 American Chemical Society.


Llera I.,Laboratorio Of Procesos Cataliticos | Mas V.,Laboratorio Of Procesos Cataliticos | Bergamini M.L.,Laboratorio Of Procesos Cataliticos | Laborde M.,Laboratorio Of Procesos Cataliticos | Amadeo N.,Laboratorio Of Procesos Cataliticos
Chemical Engineering Science | Year: 2012

In this work a kinetic study of steam reforming of ethanol using a nickel based catalyst in the temperature range 873-923K was performed. Conversion monotonically increases with space time and temperature. At 923K we obtained more than 5mol of hydrogen per mole of ethanol. This hydrogen yield is high compared to values reported in the literature. CO yield increases with the space time and temperature while CO 2 yield has a maximum at 923K, which coincides with the space time at which the system reaches complete conversion. At larger residence time CO 2 yield decreases. CH 4 yield is very low for all conditions studied but a maximum can also be seen with space time. Both CO 2 and CH 4 are intermediate products, while CO is a final product. The effect of adding H 2 to the feed was studied. Analyzing the kinetic results we propose a model involving the following reactions:(E1) CH 3CH 2OH→CO+CH 4+H 2(E1) CH 3CH 2OH+H 2O→CO 2+CH 4+ 2H 2(R1) CO 2+H 2↔CO+H 2OThe first two involving ethanol are irreversible while the latter two are reversible. The surface reactions are the rate determining steps. Kinetic parameters were estimated using commercial software. © 2011 Elsevier Ltd.

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