Search results for: Graciela Baronetti

Items from 1 to 20 out of 21 results

article

Pr3+ surface fraction in CePr mixed oxides determined by XPS analysis

Eduardo Poggio-Fraccari, Graciela Baronetti, Fernando Mariño

Journal of Electron Spectroscopy and Related Phenomena > 2018 > 222 > C > 1-4

CePr mixed oxides were previously studied as supports for Water Gas Shift catalysts, considering their promising textural and redox properties arising from the presence of a non-stoichiometric oxide. A very small Ce³⁺ fraction was observed on those oxides, suggesting that Pr³⁺ion could be responsible for the enhanced activity. Therefore, in-depth XPS analysis is conducted in the present work in order...

article

Ni/Ce0.95M0.05O2−d (M = Zr, Pr, La) for methane steam reforming at mild conditions

Ignacio Iglesias, Graciela Baronetti, Fernando Mariño

International Journal of Hydrogen Energy > 2017 > 42 > 50 > 29735- 29744

Methane obtained from renewable resources such as biogas or biomass gasification may be reformed to produce hydrogen, an important and environmentally friendly energy vector. In the present work, nickel based catalysts supported on either pure or doped ceria (5 at% of Zr, Pr or La doping) were studied for this purpose. Catalysts were obtained by impregnation of 5 wt% nickel of ceria based supports...

article

Ceria and Ce0.95M0.05O2−δ mixed oxides (M=La, Pr, Zr): Vacancies and reducibility study

Ignacio Iglesias, Graciela Baronetti, Fernando Mariño

Solid State Ionics > 2017 > 309 > C > 123-129

Highly reducible and redox active mixed oxides are employed in selective oxidation reactions and fuel cells, among others. Ceria is a renowned material in these applications because of its capacity to take and release oxygen. At the same time, these properties may be enhanced by cerium substitution with certain elements, usually, other rare earths. In this line, the present work is focused on the...

article

Cu and/or Ni catalysts over CePr oxide for the water gas shift reaction: an experimental study, kinetic fitting and reactor simulation

Eduardo Poggio-Fraccari, Pablo Giunta, Graciela Baronetti, Fernando Mariño

Reaction Kinetics, Mechanisms and Catalysis > 2017 > 121 > 2 > 607-628

Several Cu and Ni samples, supported over Pr-promoted ceria, were characterized and tested as water gas shift (WGS) catalysts in the temperature range 250–450 °C. Three metal loadings were studied, 5, 10 and 20 wt%. Redox (TPR) and textural (XRD and BET) properties were correlated with the observed catalytic behavior. The activity clearly increased with metal loading (Cu or Ni) from 5 to 10 wt%, but...

article

Egg-shell CuO/CeO2/Al2O3 catalysts for CO preferential oxidation

Fernando Mariño, Ignacio Iglesias, Graciela Baronetti, Luis Alemany, more

International Journal of Hydrogen Energy > 2015 > 40 > 34 > 11235- 11241

Catalytic systems based on copper and cerium supported on γ-Al₂O₃ have shown to be extremely effective for CO preferential oxidation. In order to selectively oxidize carbon monoxide, it is desired that only CO can access to the active sites. Since the effective diffusion of H₂ is higher than that of CO, an egg-shell type distribution is preferred. With the objective of modifying the radial distribution...

article

Ce-Pr mixed oxides as active supports for Water-gas Shift reaction: Experimental and density functional theory characterization

Eduardo Poggio-Fraccari, Beatriz Irigoyen, Graciela Baronetti, Fernando Mariño

Applied Catalysis A: General > 2014 > 485 > C > 123-132

Experimental measurements by several techniques and density functional theory (DFT) calculations are combined to characterize Ce-Pr mixed oxides and deeply understand the influence of Pr dopant in their geometric and electronic structure, reducibility and catalytic behavior concerning the Water-gas Shift reaction (WGSR). Samples with nominal Pr dopant content of 0, 5, 15 and 50at% (atomic percentage)...

article

Ce–Mn mixed oxides as supports of copper- and nickel-based catalysts for water–gas shift reaction

Eduardo Poggio Fraccari, Oriana D’Alessandro, Jorge Sambeth, Graciela Baronetti, more

Fuel Processing Technology > 2014 > 119 > Complete > 67-73

Cerium-manganese mixed oxides with different composition were prepared by co-precipitation, characterized and evaluated for the water–gas shift (WGS) reaction. Base metal (5wt.% Cu and 5wt.% 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...

article

Copper and nickel catalysts supported on praseodymium-doped ceria (PDC) for the water-gas shift reaction

Eduardo Poggio-Fraccari, Fernando Mariño, Miguel Laborde, Graciela Baronetti

Applied Catalysis A, General > 2013 > 460-461 > Complete > 15-20

The aim of this work is to study the behavior of Cu and Ni catalysts supported on praseodymium-doped ceria (PDC) for the WGS reaction. Samples were prepared by impregnation of several PDC supports (praseodymium content in the range 0–50wt%) synthesized by the urea thermal decomposition method. Bare support and catalysts were characterized by BET, XRD, oxygen storage capacity and TPR. The activity...

article

Efficient and suitable preparation of N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and ring analogues using recyclable H6P2W18O62·24H2O/SiO2 catalyst

Gustavo Pasquale, Diego Ruiz, Juan Autino, Graciela Baronetti, more

Comptes rendus - Chimie > 2012 > 15 > 9 > 758-763

Silica gel-supported H ₆ P ₂ W ₁₈ O ₆₂ ·24H ₂ O is an efficient and recyclable catalyst for the synthesis of biologically important molecules. Several substituted N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and ring analogues can be prepared in very good yields and purity by direct reaction of N-aralkylsulfonamides and sym-trioxane by a Pictet-Spengler reaction...

article

Catalytic upgrading of levulinic acid to ethyl levulinate using reusable silica-included Wells-Dawson heteropolyacid as catalyst

Gustavo Pasquale, Patricia Vázquez, Gustavo Romanelli, Graciela Baronetti

Catalysis Communications > 2012 > 18 > Complete > 115-120

In this paper we report, for the first time, the direct incorporation of a heteropolyacid (HPA) with Wells-Dawson structure during the synthesis of silica by the sol–gel technique, in acidic media, using tetraethyl orthosilicate. The catalyst characterization was carried out by ³¹ P MAS-NMR, FT-IR, XRD, N ₂ adsorption–desorption measurements, and the acidic properties were determined...

article

Influence of the calcination temperature on the structure and reducibility of nanoceria obtained from crystalline Ce(OH)CO3 precursor

Eduardo Poggio, Matías Jobbágy, Máximo Moreno, Miguel Laborde, more

International Journal of Hydrogen Energy > 2011 > 36 > 24 > 15899- 15905

A high yield green method was developed for the preparation of reactive nanotextured ceria (CeO ₂ ). The preparation method is based on the oxidation of a crystalline Ce(OH)CO ₃ precursor that decompose at relative low temperature (ca. 250 °C) yielding CeO ₂ nanocrystals initially rich in Ce ³⁺ . After increasing calcination temperatures (in the range 350–650 °C), PXRD...

article

Ni(II)–Mg(II)–Al(III) catalysts for hydrogen production from ethanol steam reforming: Influence of the activation treatments

Adriana Romero, Matías Jobbágy, Miguel Laborde, Graciela Baronetti, more

Catalysis Today > 2010 > 149 > 3-4 > 407-412

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:...

article

Catalytic performance of a copper–promoted CeO2 catalyst in the CO oxidation: Influence of the operating variables and kinetic study

Betina Schönbrod, Fernando Mariño, Graciela Baronetti, Miguel Laborde

International Journal of Hydrogen Energy > 2009 > 34 > 9 > 4021-4028

A study of the CO oxidation reaction was conducted on a CuO–CeO ₂ catalyst, with a copper content of 20at%. The stability, activity and selectivity of this sample were evaluated in the absence of H ₂ and also under PROX conditions (i.e. in great H ₂ excess). The influence of the reaction temperature and the feed composition was also analyzed. It was found that water and CO...

article

Ni(II)-Al(III) layered double hydroxide as catalyst precursor for ethanol steam reforming: Activation treatments and kinetic studies

Verónica Mas, María L. Dieuzeide, Matías Jobbágy, Graciela Baronetti, more

Catalysis Today > 2008 > 133-135 > Complete > 319-323

The kinetic behaviour of the steam reforming reaction using Ni(II)-Al(III) layered double hydroxide (LDH) as catalyst precursor is studied. The carbonate form of Ni(II)-Al(III) LDH (takovite) was prepared using an homogeneous alkalinization procedure, by means of the thermal hydrolysis of urea. Different activation treatments of Ni(II)Al(III) precursor are analysed; it was found that the catalyst...

article

CO preferential oxidation over CuO–CeO2 catalysts synthesized by the urea thermal decomposition method

Fernando Mariño, Betina Schönbrod, Máximo Moreno, Matías Jobbágy, more

Catalysis Today > 2008 > 133-135 > Complete > 735-742

CuO–CeO ₂ catalyst precursors were synthesized by the homogeneous thermal decomposition of urea. Catalysts containing different Cu/Ce ratios were obtained by calcinating the precursors at 450°C and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX) and temperature-programmed reduction (TPR) measurements. Catalytic tests were performed in the temperature range...

article

Optimized CuO–CeO2 catalysts for COPROX reaction

Fernando Mariño, Graciela Baronetti, Miguel Laborde, Nicolas Bion, more

International Journal of Hydrogen Energy > 2008 > 33 > 4 > 1345-1353

CuO–CeO2 catalyst precursors were synthesized by homogeneous thermal decomposition of urea. Catalysts containing different Cu/Ce ratios were obtained after calcination of the precursors at 450∘C and characterized by ICP-OES, N2 adsorption, XRD and TPR. Catalytic tests were performed in the temperature range 100–300∘C to evaluate the activity of these samples for the COPROX reaction. A strong synergy...

article

Synthesis of Copper-Promoted CeO ₂ Catalysts

Matías Jobbágy, Fernando Mariño, Betina Schönbrod, Graciela Baronetti, more

Chemistry of Materials > 2006 > 18 > 7 > 1945 - 1950

article

Hydrogen production via catalytic gasification of ethanol. A mechanism proposal over copper-nickel catalysts

Fernando Mariño, Marcelo Boveri, Graciela Baronetti, Miguel Laborde

International Journal of Hydrogen Energy > 2004 > 29 > 1 > 67-71

Ethanol gasification using Cu-Ni-K/γ-Al ₂ O ₃ catalysts was studied. The reaction was carried out at a low temperature (300 ^o C) and atmospheric pressure. The influence of the diffusional effects, the residence time and the water/ethanol molar ratio in the feed on the ethanol conversion and on the product distribution was analysed. Additional experiments were performed with...

article

Efficient method for tetrahydropyranylation/depyranylation of phenols and alcohols using a solid acid catalyst with Wells-Dawson structure

Gustavo P. Romanelli, Graciela Baronetti, Horacio J. Thomas, Juan C. Autino

Tetrahedron Letters > 2002 > 43 > 42 > 7589 - 7591

A simple and efficient procedure to form 2-tetrahydropyranyl acetals of phenols and alcohols is reported. Wells-Dawson heteropolyacid catalyst is used both in bulk form or supported on silica, reaction conditions include room temperature and toluene as solvent. Fast deprotection of THP-acetals can be attained by mere change of the solvent using THF-1% MeOH. In both reactions the supported catalyst...

article

Cu-Ni-K/γ-Al ₂ O ₃ supported catalysts for ethanol steam reforming - Formation of hydrotalcite-type compounds as a result of metal-support interaction

Fernando Mariño, Graciela Baronetti, Matı́as Jobbagy, Miguel Laborde

Applied Catalysis A, General > 2002 > 238 > 1 > 41-54

The interaction of Cu ² ⁺ , Ni ² ⁺ and Al ³ ⁺ ions during the impregnation step of K/γ-Al ₂ O ₃ support was studied. Cu-Ni catalyst precursors (''just impregnated solids''), just reduced precursors (H ₂ , 300 ^o C), and calcined precursors in the range of 400-800 ^o C were characterised by X-ray diffraction (XRD), temperature...

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Search results for: Graciela Baronetti

Pr3+ surface fraction in CePr mixed oxides determined by XPS analysis

Ni/Ce0.95M0.05O2−d (M = Zr, Pr, La) for methane steam reforming at mild conditions

Ceria and Ce0.95M0.05O2−δ mixed oxides (M=La, Pr, Zr): Vacancies and reducibility study

Cu and/or Ni catalysts over CePr oxide for the water gas shift reaction: an experimental study, kinetic fitting and reactor simulation

Egg-shell CuO/CeO2/Al2O3 catalysts for CO preferential oxidation

Ce-Pr mixed oxides as active supports for Water-gas Shift reaction: Experimental and density functional theory characterization

Ce–Mn mixed oxides as supports of copper- and nickel-based catalysts for water–gas shift reaction

Copper and nickel catalysts supported on praseodymium-doped ceria (PDC) for the water-gas shift reaction

Efficient and suitable preparation of N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and ring analogues using recyclable H6P2W18O62·24H2O/SiO2 catalyst

Catalytic upgrading of levulinic acid to ethyl levulinate using reusable silica-included Wells-Dawson heteropolyacid as catalyst

Influence of the calcination temperature on the structure and reducibility of nanoceria obtained from crystalline Ce(OH)CO3 precursor

Ni(II)–Mg(II)–Al(III) catalysts for hydrogen production from ethanol steam reforming: Influence of the activation treatments

Catalytic performance of a copper–promoted CeO2 catalyst in the CO oxidation: Influence of the operating variables and kinetic study

Ni(II)-Al(III) layered double hydroxide as catalyst precursor for ethanol steam reforming: Activation treatments and kinetic studies

CO preferential oxidation over CuO–CeO2 catalysts synthesized by the urea thermal decomposition method

Optimized CuO–CeO2 catalysts for COPROX reaction

Synthesis of Copper-Promoted CeO ₂ Catalysts

Hydrogen production via catalytic gasification of ethanol. A mechanism proposal over copper-nickel catalysts

Efficient method for tetrahydropyranylation/depyranylation of phenols and alcohols using a solid acid catalyst with Wells-Dawson structure

Cu-Ni-K/γ-Al ₂ O ₃ supported catalysts for ethanol steam reforming - Formation of hydrotalcite-type compounds as a result of metal-support interaction

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