Synthesis of Nanostructured Catalytic Materials from Microemulsions

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (15 December 2014) | Viewed by 46574

Special Issue Editors


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Guest Editor
Division of Chemical Technology, School of Chemistry, Kungliga Tekniska Högskolan (KTH), Teknikringen 42, SE-10044, Stockholm, Sweden
Interests: design, synthesis and characterization of nanostructured catalysts in microemulsion media; molecular structure-performance relationships at the surface of functional materials; heterogeneous catalysis (production of biofuels from gasified biomass and natural gas such as diesel, ethanol via the following catalytic processes: fisher tropsch, water gas shift, hydro-cracking, partial oxidation or catalytic combustion etc.); functionalized nanostructured materials for water treatment

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Guest Editor
Centro de Investigacion en Materiales Avanzados (CIMAV, S.C.), Unidad Monterrey, Alianza Norte 202, 66600 Apodaca, Nuevo Leon, Mexico
Interests: Design and synthesis of nanostructured materials in microemulsion media, including hybrid nanocrystals and hierarchical nanostructures;Nanomaterials for photocatalysis (degradation of contaminants and hydrogen production by water splitting) and for heterogeneous catalysis;Nanomaterials for antibacterial and electronic applications; Functionalization of nanomaterials and their incorporation into nanocomposites for various applications; Surfactant systems (microemulsions, nanoemulsions, emulsions, vesicles) for household applications

Special Issue Information

Dear Colleagues,

There is a growing interest in the use of the microemulsion method for synthesizing nanostructured catalysts. This method offers several advantages over alternative methods: namely, the use of simple equipment, the possibility of preparing a great variety of materials with a high degree of particle size and composition control, the formation of nanoparticles that oftentimes possess crystalline structure and high specific surface area, and the use of soft conditions of synthesis that are near ambient temperature and pressure.

Materials synthesized with the (water-in-oil) w/o microemulsion method exhibit unique surface properties. For example, nano-catalysts prepared by this method show better performance (i.e., in terms of activity and selectivity) than those prepared by other methods. Recent advances have also broadened the scope of the microemulsion method’s utility (with regard to nanoparticle synthesis). Water-in-oil (w/o) microemulsion method has been used since 1982. Since then, novel approaches that are based on oil-in-water (o/w) and bicontinuous microemulsions have emerged over the last four years, and the materials synthesized by these methods are also being evaluated as catalysts.

This Special Issue will focus on recent progress in the catalytic applications of nanostructured materials synthesized by microemulsion-based methods. We invite contributions regarding all types of heterogeneous catalysis applications, including photo-catalysis and electro-catalysis.

Associate Prof. Dr. Magali Boutonnet
Dr. Margarita Sanchez-Dominguez
Guest Editors

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Keywords

  • microemulsion
  • nanoreactors
  • nanoparticles
  • noble metal
  • metal
  • metal oxide
  • catalyst support
  • catalyst preparation
  • heterogeneous catalysis

Published Papers (6 papers)

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Editorial

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161 KiB  
Editorial
Synthesis of Nanostructured Catalytic Materials from Microemulsions
by Margarita Sanchez-Dominguez and Magali Boutonnet
Catalysts 2016, 6(1), 4; https://doi.org/10.3390/catal6010004 - 25 Dec 2015
Cited by 7 | Viewed by 3662
Abstract
Since the 1980s [1,2], colloidal systems such as microemulsions (ME) have been widely investigated, especially for the synthesis of nanomaterials for various applications.[...] Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)

Research

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10957 KiB  
Article
Design of Cobalt Nanoparticles with Tailored Structural and Morphological Properties via O/W and W/O Microemulsions and Their Deposition onto Silica
by Gabriella Di Carlo, Matteo Lualdi, Anna M. Venezia, Magali Boutonnet and Margarita Sanchez-Dominguez
Catalysts 2015, 5(1), 442-459; https://doi.org/10.3390/catal5010442 - 19 Mar 2015
Cited by 17 | Viewed by 7177
Abstract
Cobalt nanostructures with different size and morphology, i.e., spherical nanoparticles, nanorods, and particles arranged into elongated structures, were prepared using micelles and microemulsions as confined reaction media. The syntheses were carried out using three types of systems: aqueous surfactant solutions, oil-in water [...] Read more.
Cobalt nanostructures with different size and morphology, i.e., spherical nanoparticles, nanorods, and particles arranged into elongated structures, were prepared using micelles and microemulsions as confined reaction media. The syntheses were carried out using three types of systems: aqueous surfactant solutions, oil-in water (O/W), and water-in-oil (W/O) microemulsions. The influence of the surfactant and the precipitating agent used for synthesis was also investigated. For this purpose, cobalt nanostructures were prepared using different non-ionic surfactants, namely Synperonic® 10/6, Pluronic® P123 and a mixture of SPAN 20–TWEEN 80. Three different precipitating agents were used: sodium borohydride, sodium hydroxide, and oxalic acid. Our findings revealed that by changing the type of reaction media as well as the precipitating agent it is possible to modify the shape and size of the cobalt nanostructures. Moreover, the use of O/W microemulsion generates better results in terms of colloidal stability and uniformity of particle size with respect to W/O microemulsion. The different cobalt nanostructures were supported on commercial and mesoporous silica; transmission electron microscopy (TEM) images showed that after deposition the Co nanocrystals remain well dispersed on the silica supports. This behavior suggests their great potential in catalytic applications. Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)
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5585 KiB  
Article
Preparation for Pt-Loaded Zeolite Catalysts Using w/o Microemulsion and Their Hydrocracking Behaviors on Fischer-Tropsch Product
by Toshiaki Hanaoka, Tomohisa Miyazawa, Katsuya Shimura and Satoshi Hirata
Catalysts 2015, 5(1), 88-105; https://doi.org/10.3390/catal5010088 - 06 Feb 2015
Cited by 7 | Viewed by 7759
Abstract
Pt-loaded β-type zeolite catalysts with constant Pt content (0.11 wt.%) and similar pore structure were prepared using a water-in-oil (w/o) microemulsion. The effect of Pt particle synthesis conditions using microemulsion (a type of Pt complex-forming agents and the molar ratio of complex-forming agent [...] Read more.
Pt-loaded β-type zeolite catalysts with constant Pt content (0.11 wt.%) and similar pore structure were prepared using a water-in-oil (w/o) microemulsion. The effect of Pt particle synthesis conditions using microemulsion (a type of Pt complex-forming agents and the molar ratio of complex-forming agent to Pt4+) on loaded Pt particle size was investigated. The Pt particle size of the Pt catalyst using tetraethylammonium chloride (TEAC) as a complex-forming agent with the molar TEAC/Pt ratio 10 was the minimum value (3.8 nm), and was much smaller than that (6.7 nm) prepared by the impregnation method. The utilization of the complex-forming agent of which hydrophobic groups occupied a small volume and the appropriate complex-forming agent/Pt ratio were favorable for synthesis of small Pt particles. The effect of loaded Pt particle size on the hydrocracking of the Fischer-Tropsch (FT) product was investigated using the Pt-loaded zeolite catalysts at 250 °C with an initial H2 pressure of 0.5 MPa, and reaction time of 1 h. The Pt catalyst with a Pt particle size of 4.2 nm prepared using the microemulsion exhibited the maximum corresponding jet fuel yield (30.0%), which was higher than that of the impregnated catalyst. Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)
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4007 KiB  
Article
How to Determine the Core-Shell Nature in Bimetallic Catalyst Particles?
by Emma Westsson and Ger J.M. Koper
Catalysts 2014, 4(4), 375-396; https://doi.org/10.3390/catal4040375 - 28 Nov 2014
Cited by 29 | Viewed by 8597
Abstract
Nanometer-sized materials have significantly different chemical and physical properties compared to bulk material. However, these properties do not only depend on the elemental composition but also on the structure, shape, size and arrangement. Hence, it is not only of great importance to develop [...] Read more.
Nanometer-sized materials have significantly different chemical and physical properties compared to bulk material. However, these properties do not only depend on the elemental composition but also on the structure, shape, size and arrangement. Hence, it is not only of great importance to develop synthesis routes that enable control over the final structure but also characterization strategies that verify the exact nature of the nanoparticles obtained. Here, we consider the verification of contemporary synthesis strategies for the preparation of bimetallic core-shell particles in particular in relation to potential particle structures, such as partial absence of core, alloying and raspberry-like surface. It is discussed what properties must be investigated in order to fully confirm a covering, pin-hole free shell and which characterization techniques can provide such information. Not uncommonly, characterization strategies of core-shell particles rely heavily on visual imaging like transmission electron microscopy. The strengths and weaknesses of various techniques based on scattering, diffraction, transmission and absorption for investigating core-shell particles are discussed and, in particular, cases where structural ambiguities still remain will be highlighted. Our main conclusion is that for particles with extremely thin or mono-layered shells—i.e., structures outside the limitation of most imaging techniques—other strategies, not involving spectroscopy or imaging, are to be employed. We will provide a specific example of Fe-Pt core-shell particles prepared in bicontinuous microemulsion and point out the difficulties that arise in the characterization process of such particles. Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)
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2638 KiB  
Article
Catalytic Activity of Mono- and Bi-Metallic Nanoparticles Synthesized via Microemulsions
by Ramona Y.G. König, Michael Schwarze, Reinhard Schomäcker and Cosima Stubenrauch
Catalysts 2014, 4(3), 256-275; https://doi.org/10.3390/catal4030256 - 01 Jul 2014
Cited by 22 | Viewed by 9601
Abstract
Water-in-oil (w/o) microemulsions were used as a template for the synthesis of mono- and bi-metallic nanoparticles. For that purpose, w/o-microemulsions containing H2PtCl6, H2PtCl6 + Pb(NO3)2 and H2PtCl6 + Bi(NO)3 [...] Read more.
Water-in-oil (w/o) microemulsions were used as a template for the synthesis of mono- and bi-metallic nanoparticles. For that purpose, w/o-microemulsions containing H2PtCl6, H2PtCl6 + Pb(NO3)2 and H2PtCl6 + Bi(NO)3, respectively, were mixed with a w/o-microemulsion containing the reducing agent, NaBH4. The results revealed that it is possible to synthesize Pt, PtPb and PtBi nanoparticles of ~3–8 nm in diameter at temperatures of about 30°C. The catalytic properties of the bimetallic PtBi and PtPb nanoparticles were studied and compared with monometallic platinum nanoparticles. Firstly, the electrochemical oxidation of formic acid to carbon monoxide was investigated, and it was found that the resistance of the PtBi and PtPb nanoparticles against the catalyst-poisoning carbon monoxide was significantly higher compared to the Pt nanoparticles. Secondly, investigating the reduction of 4-nitrophenol to 4-aminophenol,we found that the bimetallic NPs are most active at 23 °C, while the order of the activity changes at higher temperatures, i.e., that the Pt nanoparticles are the most active ones at 36 and 49 °C. Furthermore, we observed a strong influence of the support, which was either a polymer or Al2O3. Thirdly, for the hydrogenation of allylbenzene to propylbenzene, the monometallic Pt NPs turned out to be the most active catalysts, followed by the PtPb and PtBi NPs. Comparing the two bimetallic nanoparticles, one sees that the PtPb NPs are significantly more active than the respective PtBi NPs. Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)
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Review

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6592 KiB  
Review
Metallic Clusters: Theoretical Background, Properties and Synthesis in Microemulsions
by David Buceta, Yolanda Piñeiro, Carlos Vázquez-Vázquez, José Rivas and Manuel Arturo López-Quintela
Catalysts 2014, 4(4), 356-374; https://doi.org/10.3390/catal4040356 - 03 Nov 2014
Cited by 51 | Viewed by 8969
Abstract
Reducing the size from the bulk material to nanoparticles produces a scaling behavior in physical properties in the later ones, due to the large surface-to-volume fraction. By further size reduction, entering into the subnanometric cluster region, physical properties are largely affected by strong [...] Read more.
Reducing the size from the bulk material to nanoparticles produces a scaling behavior in physical properties in the later ones, due to the large surface-to-volume fraction. By further size reduction, entering into the subnanometric cluster region, physical properties are largely affected by strong quantum confinement. These quantum size effects (HOMO-LUMO gap), the small size and the specific geometry award subnanometric clusters with totally new and fascinating properties, including cluster photoluminescence, enhanced catalytic activity, etc. In this review, we report an introduction to the physical properties of clusters based on the jellium model; the controlled synthesis by microemulsion methods and the catalytic properties in different areas as heterogeneous catalysis, photocatalysis or electrocatalysis among others. Full article
(This article belongs to the Special Issue Synthesis of Nanostructured Catalytic Materials from Microemulsions)
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