The effect of the type of dopant (titanium and manganese) and of the reduced graphene oxide content (rGO, 30 or 50 wt %) of the α-Fe2O3@rGO nanocomposites on their microstructural properties and electrochemical performance was... more
The effect of the type of dopant (titanium and manganese) and of the reduced graphene oxide content (rGO, 30 or 50 wt %) of the α-Fe2O3@rGO nanocomposites on their microstructural properties and electrochemical performance was investigated. Nanostructured composites were synthesized by a simple one-step solvothermal method and evaluated as anode materials for sodium ion batteries. The doping does not influence the crystalline phase and morphology of the iron oxide nanoparticles, but remarkably increases stability and Coulombic efficiency with respect to the anode based on the composite α-Fe2O3@rGO. For fixed rGO content, Ti-doping improves the rate capability at lower rates, whereas Mn-doping enhances the electrode stability at higher rates, retaining a specific capacity of 56 mAhg−1 at a rate of 2C. Nanocomposites with higher rGO content exhibit better electrochemical performance.
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Transition metal oxides on reduced graphene oxide (TMO@rGO) nanocomposites were successfully prepared via a very simple one-step solvothermal process, involving the simultaneous (thermal) reduction of graphene oxide to graphene and the... more
Transition metal oxides on reduced graphene oxide (TMO@rGO) nanocomposites were successfully prepared via a very simple one-step solvothermal process, involving the simultaneous (thermal) reduction of graphene oxide to graphene and the deposition of TMO nanoparticles over its surface. Texture and morphology, microstructure, and chemical and surface compositions of the nanocomposites were investigated via scanning electron microscopy, X-ray diffraction, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results prove that Fe2O3@rGO, CoFe2O4@rGO, and CoO@rGO are obtained by using Fe and/or Co acetates as oxide precursors, with the TMO nanoparticles uniformly anchored onto the surface of graphene sheets. The electrochemical performance of the most promising nanocomposite was evaluated as anode material for sodium ion batteries. The preliminary results of galvanostatic cycling prove that Fe2O3@rGO nanocomposite exhibits better rate capability and stability...
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ABSTRACT A microstructural characterization by XRD, FT-IR and temperature programmed reduction (TPR) of unsupported FeV and K-FeV catalysts, prepared by solid-state synthesis, is reported. The formation of FexVyOz mixed phases of... more
ABSTRACT A microstructural characterization by XRD, FT-IR and temperature programmed reduction (TPR) of unsupported FeV and K-FeV catalysts, prepared by solid-state synthesis, is reported. The formation of FexVyOz mixed phases of different compositions has been evidenced depending on the V/Fe ratio and calcination temperature. The catalytic activity of the samples in the combustion of diesel soot has been investigated with the aim to understand the role of FexVyOz mixed phases in the title reaction.
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... References. 1. AF Ahlstrom and CUI Odenbrand. Appl. Catal. 60 (1990), p. 157. View Record in Scopus | Cited By in Scopus (62). 2. J. Van Doorn, J. Varloud, P. Mériaudeau, V. Perrichon, M. Chevrier and C. Gauthier. Appl. Catal. B:... more
... References. 1. AF Ahlstrom and CUI Odenbrand. Appl. Catal. 60 (1990), p. 157. View Record in Scopus | Cited By in Scopus (62). 2. J. Van Doorn, J. Varloud, P. Mériaudeau, V. Perrichon, M. Chevrier and C. Gauthier. Appl. Catal. B: Environ. 1 (1992), p. 117. ...
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Liquid phase hydrogenation and isomerization of some α,β-unsaturated primary and secondary alcohols have been investigated in tetrahydrofuran over a 2.5% TiO2 supported palladium catalyst at 303K and 0.01MPa partial hydrogen pressure. The... more
Liquid phase hydrogenation and isomerization of some α,β-unsaturated primary and secondary alcohols have been investigated in tetrahydrofuran over a 2.5% TiO2 supported palladium catalyst at 303K and 0.01MPa partial hydrogen pressure. The double bond isomerization reaction of these substrates leads also to formation of the corresponding saturated aldehydes or ketones. Catalytic activity and selectivity were found to depend strongly on the steric and electronic effects of the substituents on the double bond of the alcohol. The less crowded is the olefinic bond of the unsaturated alcohol, the higher is the activity. Formation of two σ-alkyl palladium bonded intermediates was postulated to explain the different selectivity towards hydrogenated and isomerized products observed for α,β-unsaturated alcohols used. 2-Propen-1-ol exhibited the highest activity and selectivity for double bond migration leading to propanal up to 80% yield.
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ABSTRACT The gas-phase interaction of cis-2-butene-1,4-diol (C-2-OL) with silica supported Pd and Pt nanoparticles has been studied using infrared spectroscopy at room temperature. Samples were prepared according to standard recipes and... more
ABSTRACT The gas-phase interaction of cis-2-butene-1,4-diol (C-2-OL) with silica supported Pd and Pt nanoparticles has been studied using infrared spectroscopy at room temperature. Samples were prepared according to standard recipes and characterized through TEM and the IR spectroscopy of adsorbed carbon monoxide at room temperature. Whereas the reaction with hydrogen of C-2-OL in ethanol solutions yields hydrogenated products through a complex network, and no reaction takes place in the absence of hydrogen, in the present case C-2-OL is converted first to 2,5-dihydrofuran (2,5-DHF) and water. This step occurs on the silica support at room temperature, probably through the intermediacy of the surface species –Si–O–CH2–CHCH–CH2–OH. The presence of Pd nanoparticles allows, at ca. 100°C, the subsequent isomerization of 2,5-DHF to 2,3-dihydrofuran (2,3-DHF). The same reaction requires a higher temperature (ca. 150°C) with the Pt catalyst. At higher temperatures, the expected dehydrogenation of both 2,5- and 2,3-DHFs to furan takes place. On the support alone at 350°C 2,5-DHF is converted to furan, and 2,3-DHF to carbonyl-containing species (as suggested in the literature), through thermal reactions.
Research Interests: Chemical Engineering, Catalysts, Heterogeneous Catalysis, Carbon Monoxide, Conversion, and 12 moreInfrared spectroscopy, Silica, Complex network, Hydrogen Production, Palladium, Room Temperature, IR Spectroscopy, Isomerization, Surface characterization, Reaction Mechanism, Infrared Spectrometry, and FT IR Spectroscopy
... Catal. A, 95 (1995) 235. [2] G. Neri, MG Musolino, C. Milone and S. Galvagno, Ind. Eng. Chem. Res., 34 (1995) 2226. [3] K. Brand and J. Steiner, Ber. Dent. Chem. Ges., 55 (1923) 883. [4] HJJanssen, AJ Kruithof, GJ Steghius and KR... more
... Catal. A, 95 (1995) 235. [2] G. Neri, MG Musolino, C. Milone and S. Galvagno, Ind. Eng. Chem. Res., 34 (1995) 2226. [3] K. Brand and J. Steiner, Ber. Dent. Chem. Ges., 55 (1923) 883. [4] HJJanssen, AJ Kruithof, GJ Steghius and KR Westerterp, Ind. Eng. Chem. ...
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... in Scheme 2. A different mechanism of reaction has been reported by Janssen et al. [ 7,8 ] . They have suggested that DNT is converted to 4HA2NT and 2A4NT through two parallel reactions, whereas 240 13 N02 CH3 H3... more
... in Scheme 2. A different mechanism of reaction has been reported by Janssen et al. [ 7,8 ] . They have suggested that DNT is converted to 4HA2NT and 2A4NT through two parallel reactions, whereas 240 13 N02 CH3 H3 ~' N02 H2 _ / I 02 2 H2 NH2 N02 Scheme 2. G. Neri et al ...
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An improved HPLC method was developed for the separation and quantification of 2,4-dinitrotoluene and its reduction products. Gradient elution, with a water–acetonitrile mobile phase, was selected for the separation of all components... more
An improved HPLC method was developed for the separation and quantification of 2,4-dinitrotoluene and its reduction products. Gradient elution, with a water–acetonitrile mobile phase, was selected for the separation of all components including the 2,4-nitrohydroxyaminotoluene isomers. Provisional identification of the isomer intermediates has been obtained by their UV–Vis spectra.
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... Similar deviations in the fitting of the concentration of the intermediate compounds have been reported by Janssen (1990b) by using the same reaction mechanism. The experimental results recently reported by us (Neri et al., 1995) have... more
... Similar deviations in the fitting of the concentration of the intermediate compounds have been reported by Janssen (1990b) by using the same reaction mechanism. The experimental results recently reported by us (Neri et al., 1995) have suggested that QA2NT is likely to be ...
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... Notwithstanding the great industrial interest for this reaction, few papers, focusing their attention on the reaction mechanism, have however appeared in the literature (Kut et al., 1987; Janssen et al, 1990a,b; Neri et al., 1995a,b).... more
... Notwithstanding the great industrial interest for this reaction, few papers, focusing their attention on the reaction mechanism, have however appeared in the literature (Kut et al., 1987; Janssen et al, 1990a,b; Neri et al., 1995a,b). In previous papers we have investigated the ...
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full... more
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is ...
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Catalytic hydrogenolysis, with high conversion and selectivity, promoted by supported palladium substrates in isopropanol and dioxane at a low H(2) pressure (0.5 MPa), is reported for the first time. The catalysts, characterized by using... more
Catalytic hydrogenolysis, with high conversion and selectivity, promoted by supported palladium substrates in isopropanol and dioxane at a low H(2) pressure (0.5 MPa), is reported for the first time. The catalysts, characterized by using BET isotherms, transmission electron microscopy (TEM), temperature-programmed reduction (TPR), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were obtained by coprecipitation and impregnation techniques. The coprecipitation method allows catalysts with a metal-metal or a metal-support interaction to be obtained, which enhances the catalytic performance for both the conversion of glycerol and the selectivity to 1,2-propanediol. Analogous reactions carried out with catalysts prepared by using impregnation are less efficient. A study of the solvent and temperature effect is also presented. The obtained results allow the hydrogenolysis mechanism to be inferred; this involves both the direct replacement of the carbon-bonded OH group by an incoming hydrogen or the formation of hydroxyacetone as an intermediate, which subsequently undergoes a hydrogenation process to give 1,2-propanediol. Finally, catalytic tests on a large-scale reaction at a higher H(2) pressure and recycling of the samples were carried out with the better performing catalysts (Pd/CoO and Pd/Fe(2)O(3) prepared by using coprecipitation) to verify possible industrial achievements.
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ABSTRACT Homogeneous hydrogenation and isomerization reaction of cis-2-butene-1,4-diol has been investigated in ethanol by using tris(triphenylphosphine)chlororhodium(I), RhCl(PPh3)3, and triethylamine at 303K and 0.01–0.1MPa partial... more
ABSTRACT Homogeneous hydrogenation and isomerization reaction of cis-2-butene-1,4-diol has been investigated in ethanol by using tris(triphenylphosphine)chlororhodium(I), RhCl(PPh3)3, and triethylamine at 303K and 0.01–0.1MPa partial hydrogen pressure. Under reduced H2 pressure, the geometric isomerization reaction occurs, to a high extent, leading to trans-2-butene-1,4-diol up to 93% selectivity at 90% conversion of the cis analogous. Effects of H2 partial pressure as well as triethylamine, added phosphine and olefin concentrations on the rate of reaction and on the products distribution were also investigated. The results obtained can be interpreted on the basis of a proposed mechanism in which RhH(PPh3)3 is the active species. The high selectivity towards cis-trans isomerization of cis-2-butene-1,4-diol is attributed to steric factors of the Rh(I) coordinated triphenylphosphine groups.
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ABSTRACT Alkali-doped FeV oxide catalysts supported on α-alumina were prepared and their catalytic activity in the combustion of diesel soot is reported. The catalysts were characterized by XRD, TPR and SEM–EDX analysis. The influence of... more
ABSTRACT Alkali-doped FeV oxide catalysts supported on α-alumina were prepared and their catalytic activity in the combustion of diesel soot is reported. The catalysts were characterized by XRD, TPR and SEM–EDX analysis. The influence of the nature of the alkali metal (K and Cs), the temperature of treatment of the catalysts and the stability to sulfur poisoning have been investigated.Catalysts doped with Cs were the most active and stable also after several combustion cycles and in the presence of sulfur in the stream. The activity measurements and microstructural results suggest that the combustion of soot is favored on catalysts where amorphous phases and/or mixed FeVO phases, ensuring an intimate contact between iron and vanadium, are present. A reaction mechanism involving the participation of the redox couple Fe(II)–Fe(III) in the activation of the vanadium combustion sites, is proposed.
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Lewis acids (FeCl3, ZnCl2, H3BO3) supported on SiO2 and TiO2 nanoparticles have been tested in the selective isomerization of α-pinene oxide to campholenic aldehyde. The spherical nanoparticle supports with a narrow particles size... more
Lewis acids (FeCl3, ZnCl2, H3BO3) supported on SiO2 and TiO2 nanoparticles have been tested in the selective isomerization of α-pinene oxide to campholenic aldehyde. The spherical nanoparticle supports with a narrow particles size distribution have been synthesized by the sol–gel method. The morphological and microstructural characterization of the supports and catalysts was carried out by XRD, SEM–EDX and BET surface
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The catalytic reduction of aliphatic aldehydes (propanal, pentanal and hexanal) and ketones (pentan-2-one, pentan-3-one and cyclohexanone) to the corresponding alcohols promoted by palladium catalysts, such as Pd/CoO, Pd/NiO, Pd/ZnO,... more
The catalytic reduction of aliphatic aldehydes (propanal, pentanal and hexanal) and ketones (pentan-2-one, pentan-3-one and cyclohexanone) to the corresponding alcohols promoted by palladium catalysts, such as Pd/CoO, Pd/NiO, Pd/ZnO, Pd/Fe2O3 and Pd/CeO2, was performed under mild conditions (0.1MPa H2 and 323K) for the first time.All the catalysts were obtained by the co-precipitation technique and characterized by BET, TPR, XRD, TEM
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The selective catalytic reduction of the unsaturated campholenic aldehyde to the corresponding unsaturated alcohol, naturanol, was investigated over 2wt.% Pd supported on different metal oxides (MeOx=SiO2, TiO2, ZnO, Fe2O3, NiO, Co3O4).... more
The selective catalytic reduction of the unsaturated campholenic aldehyde to the corresponding unsaturated alcohol, naturanol, was investigated over 2wt.% Pd supported on different metal oxides (MeOx=SiO2, TiO2, ZnO, Fe2O3, NiO, Co3O4). Pd/MeOx catalysts have been prepared by impregnation (series I) and coprecipitation (series CP) and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and temperature programmed reduction (TPR).Results obtained
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ABSTRACT The liquid phase hydrogenation of cis-2-butene-1,4-diol over a supported palladium catalyst has been investigated in ethanol at 0.01≤PH2≤0.5MPa and 273≤T≤303K. The effect of substrate concentration, catalyst amount, agitation... more
ABSTRACT The liquid phase hydrogenation of cis-2-butene-1,4-diol over a supported palladium catalyst has been investigated in ethanol at 0.01≤PH2≤0.5MPa and 273≤T≤303K. The effect of substrate concentration, catalyst amount, agitation speed and H2 pressure on the reaction rate has also been studied under isothermal conditions. Under reduced H2 pressure, double bond isomerization reaction occurs to a high extent leading to 2-hydroxytetrahydrofuran up to 60% yield. Formation of all reaction products was explained on the basis of a reaction model in which a surface σ-alkyl derivative was postulated and the results were clarified on applying the steady-state approximation to this intermediate. Kinetic rate equations were derived following the Langmuir–Hinshelwood model by assuming a non-competitive adsorption of organic species and hydrogen on the palladium active sites. Rate constants and the adsorption constant for each reaction were determined by a non-linear regression analysis. An excellent agreement between the predicted concentrations versus time profiles and the experimental data was observed. Furthermore, the model predictions of hydrogenated and isomerized compounds formation at different pressures agree well with the experimental results obtained.
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The effect of K, Ca and Ba metals addition on the catalytic properties of SiO2 supported ruthenium catalysts in the selective liquid phase conversion of cis-2-butene-1,4-diol affording, when hydrogenated, 2-hydroxytetrahydrofuran has been... more
The effect of K, Ca and Ba metals addition on the catalytic properties of SiO2 supported ruthenium catalysts in the selective liquid phase conversion of cis-2-butene-1,4-diol affording, when hydrogenated, 2-hydroxytetrahydrofuran has been investigated. Catalysts containing 5wt% Ru and promoted with a different amount of selected first and second group metals salts have been prepared and characterized by TPR, XRD, TEM,
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Bifunctional Pt-Sn/SiO2 catalysts with different Sn/Pt ratios have been prepared by co-impregnation, reduced in H2 and tested by means of the one-pot synthesis of α-campholenic alcohol (naturanol) from α-pinene oxide. All results are... more
Bifunctional Pt-Sn/SiO2 catalysts with different Sn/Pt ratios have been prepared by co-impregnation, reduced in H2 and tested by means of the one-pot synthesis of α-campholenic alcohol (naturanol) from α-pinene oxide. All results are reported in two sections. In Part I, here presented, characterization of catalysts in terms of microstructure chemical and surface properties by X-ray diffraction (XRD), transmission electron microscopy
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Palladium catalysts on different supports (SiO2, Al2O3, TiO2, ZrO2, MgO and ZnO) have been tested in selective liquid phase conversion of cis-2-butene-1,4-diol affording also, when hydrogenated, 2-hydroxytetrahydrofuran. The metal... more
Palladium catalysts on different supports (SiO2, Al2O3, TiO2, ZrO2, MgO and ZnO) have been tested in selective liquid phase conversion of cis-2-butene-1,4-diol affording also, when hydrogenated, 2-hydroxytetrahydrofuran. The metal particle size was determined by TEM. The acidic properties of the catalysts were studied by FT-IR spectroscopy using pyridine as probe molecule. The influence of some preparative variables, such as the