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1362 KiB

Open AccessArticle

Highly Dispersed Nickel-Containing Mesoporous Silica with Superior Stability in Carbon Dioxide Reforming of Methane: The Effect of Anchoring

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Materials 2014, 7(3), 2340-2355; https://doi.org/10.3390/ma7032340 - 19 Mar 2014

Cited by 61 | Viewed by 10594

Abstract

A series of nickel-containing mesoporous silica samples (Ni-SiO₂) with different nickel content (3.1%–13.2%) were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO₂ [...] Read more.

A series of nickel-containing mesoporous silica samples (Ni-SiO₂) with different nickel content (3.1%–13.2%) were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO₂, with highly dispersed small nickel particles, exhibited excellent catalytic activity and long-term stability. The metallic nickel particle size was significantly affected by the metal anchoring effect between metallic nickel particles and unreduced nickel ions in the silica matrix. A strong anchoring effect was suggested to account for the remaining of small Ni particle size and the improved catalytic performance. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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724 KiB

Open AccessArticle

Selective Preparation of trans-Carveol over Ceria Supported Mesoporous Materials MCM-41 and SBA-15

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Nariman F. Salakhutdinov

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Dmitry Yu. Murzin

Materials 2013, 6(5), 2103-2118; https://doi.org/10.3390/ma6052103 - 17 May 2013

Cited by 31 | Viewed by 6890

Abstract

Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce–Si–MCM-41, 16 wt % Ce–H–MCM-41 and 20 wt % Ce–Si–SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were [...] Read more.

Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce–Si–MCM-41, 16 wt % Ce–H–MCM-41 and 20 wt % Ce–Si–SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were performed using scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and FTIR pyridine adsorption. Selective preparation of trans-carveol was carried out in the liquid phase in a batch reactor. The activity and the selectivity of catalyst were observed to be influenced by their acidity, basicity and morphology of the mesoporous materials. The formation of trans-carveol is moreover strongly influenced by the basicity of the used solvent and in order to achieve high yields of this desired alcohol it is necessary to use polar basic solvent. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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885 KiB

Open AccessArticle

Simple Preparation of Novel Metal-Containing Mesoporous Starches

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Manuel Ojeda

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Vitaliy Budarin

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Peter S. Shuttleworth

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Materials 2013, 6(5), 1891-1902; https://doi.org/10.3390/ma6051891 - 10 May 2013

Cited by 8 | Viewed by 6276

Abstract

Metal-containing mesoporous starches have been synthesized using a simple and efficient microwave-assisted methodology followed by metal impregnation in the porous gel network. Final materials exhibited surface areas >60 m² g⁻¹, being essentially mesoporous with pore sizes in the 10–15 nm [...] Read more.

Metal-containing mesoporous starches have been synthesized using a simple and efficient microwave-assisted methodology followed by metal impregnation in the porous gel network. Final materials exhibited surface areas >60 m² g⁻¹, being essentially mesoporous with pore sizes in the 10–15 nm range with some developed inter-particular mesoporosity. These materials characterized by several techniques including XRD, SEM, TG/DTA and DRIFTs may find promising catalytic applications due to the presence of (hydr)oxides in their composition. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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1396 KiB

Open AccessArticle

From Waste to Healing Biopolymers: Biomedical Applications of Bio-Collagenic Materials Extracted from Industrial Leather Residues in Wound Healing

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Materials 2013, 6(5), 1599-1607; https://doi.org/10.3390/ma6051599 - 29 Apr 2013

Cited by 13 | Viewed by 6312

Abstract

The biomedical properties of a porous bio-collagenic polymer extracted from leather industrial waste residues have been investigated in wound healing and tissue regeneration in induced wounds in rats. Application of the pure undiluted bio-collagen to induced wounds in rats dramatically improved its healing [...] Read more.

The biomedical properties of a porous bio-collagenic polymer extracted from leather industrial waste residues have been investigated in wound healing and tissue regeneration in induced wounds in rats. Application of the pure undiluted bio-collagen to induced wounds in rats dramatically improved its healing after 7 days in terms of collagen production and wound filling as well as in the migration and differentiation of keratinocytes. The formulation tested was found to be three times more effective than the commercial reference product Catrix^® (Heal Progress (HP): 8 ± 1.55 vs. 2.33 ± 0.52, p < 0.001; Formation of Collagen (FC): 7.5 ± 1.05 vs. 2.17 ± 0.75, p < 0.001; Regeneration of Epidermis (RE): 13.33 ± 5.11 vs. 5 ± 5.48, p < 0.05). Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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781 KiB

Open AccessArticle

Preparation of Palladium-Supported Periodic Mesoporous Organosilicas and their Use as Catalysts in the Suzuki Cross-Coupling Reaction

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César Jiménez-Sanchidrián

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Francisco J. Romero-Salguero

Materials 2013, 6(4), 1554-1565; https://doi.org/10.3390/ma6041554 - 17 Apr 2013

Cited by 26 | Viewed by 6014

Abstract

Three periodic mesoporous materials, i.e., two organosilicas with either ethylene or phenylene bridges and one silica, have been used as supports for Pd nanoparticles. All Pd-supported samples (1.0 wt%) were prepared by the incipient wetness method and subsequently reduced in an H [...] Read more.

Three periodic mesoporous materials, i.e., two organosilicas with either ethylene or phenylene bridges and one silica, have been used as supports for Pd nanoparticles. All Pd-supported samples (1.0 wt%) were prepared by the incipient wetness method and subsequently reduced in an H₂ stream at 200 °C. Both hydrogen chemisorption and temperature programmed reduction experiments revealed significant differences depending on the support. Pd²⁺ species were more reducible on the mesoporous organosilicas than on their silica counterpart. Also, remarkable differences on the particle morphology were observed by transmission electron microscopy. All Pd-supported samples were active in the Suzuki cross-coupling reaction between bromobenzene and phenylboronic acid. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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763 KiB

Open AccessArticle

Extraction of Perchlorate Using Porous Organosilicate Materials

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Materials 2013, 6(4), 1403-1419; https://doi.org/10.3390/ma6041403 - 02 Apr 2013

Cited by 1 | Viewed by 5150

Abstract

Sorbent materials were developed utilizing two morphological structures, comprising either hexagonally packed pores (HX) or a disordered pore arrangement (CF). The sorbents were functionalized with combinations of two types of alkylammonium groups. When capture of perchlorate by the sorbents was compared, widely varying [...] Read more.

Sorbent materials were developed utilizing two morphological structures, comprising either hexagonally packed pores (HX) or a disordered pore arrangement (CF). The sorbents were functionalized with combinations of two types of alkylammonium groups. When capture of perchlorate by the sorbents was compared, widely varying performance was noted as a result of differing morphology and/or functional group loading. A material providing improved selectivity for perchlorate over perrhenate was synthesized with a CF material using N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride. Materials were applied in batch and column formats. Binding isotherms followed the behavior expected for a system in which univalent ligands of varying affinity compete for immobilized sites. Performance of the sorbents was also compared to that of commercial Purolite materials. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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2664 KiB

Open AccessArticle

Grafting of Amines on Ethanol-Extracted SBA-15 for CO₂Adsorption

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Materials 2013, 6(3), 981-999; https://doi.org/10.3390/ma6030981 - 12 Mar 2013

Cited by 60 | Viewed by 9189

Abstract

SBA-15 prepared via ethanol extraction for template removing was grafted with three kinds of amine precursors (mono-, di-, tri-aminosilanes) to synthesis new CO₂ adsorbents. The SBA-15 support and the obtained adsorbents were characterized by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), N [...] Read more.

SBA-15 prepared via ethanol extraction for template removing was grafted with three kinds of amine precursors (mono-, di-, tri-aminosilanes) to synthesis new CO₂ adsorbents. The SBA-15 support and the obtained adsorbents were characterized by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), N₂ adsorption/desorption, thermogravimetry (TG), elemental analysis, Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that, except higher silanol density, the ethanol-extracted SBA-15 support possessed a more regular mesophase and thicker walls than traditionally calcined samples, leading to a good stability of the adsorbent under steam treatment. The adsorption capacity of different amine-grafted samples was found to be influenced by not only the surface amine density, but also their physiochemical properties. These observations provide important support for further studies of applying amine-grafted adsorbents in practical CO₂ capture process. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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329 KiB

Open AccessArticle

Pore Narrowing of Mesoporous Silica Materials

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Christophe Detavernier

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Isabel Van Driessche

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Pascal Van Der Voort

Materials 2013, 6(2), 570-579; https://doi.org/10.3390/ma6020570 - 20 Feb 2013

Cited by 3 | Viewed by 6702

Abstract

To use mesoporous silicas as low-k materials, the pore entrances must be really small to avoid diffusion of metals that can increase the dielectric constant of the low-k dielectric. In this paper we present a new method to narrow the pores of mesoporous [...] Read more.

To use mesoporous silicas as low-k materials, the pore entrances must be really small to avoid diffusion of metals that can increase the dielectric constant of the low-k dielectric. In this paper we present a new method to narrow the pores of mesoporous materials through grafting of a cyclic-bridged organosilane precursor. As mesoporous material, the well-studied MCM-41 powder was selected to allow an easy characterization of the grafting reactions. Firstly, the successful grafting of the cyclic-bridged organosilane precursor on MCM-41 is presented. Secondly, it is demonstrated that pore narrowing can be obtained without losing porosity by removing the porogen template after grafting. The remaining silanols in the pores can then be end-capped with hexamethyl disilazane (HMDS) to make the material completely hydrophobic. Finally, we applied the pore narrowing method on organosilica films to prove that this method is also successful on existing low-k materials. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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664 KiB

Open AccessArticle

Hemostatic Efficiency and Wound Healing Properties of Natural Zeolite Granules in a Lethal Rabbit Model of Complex Groin Injury

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Materials 2012, 5(12), 2586-2596; https://doi.org/10.3390/ma5122586 - 03 Dec 2012

Cited by 27 | Viewed by 8707

Abstract

Quikclot has been used many years for treating external hemorrhage in the battle field. In this study, the hemostatic performance of NZG-JY (natural zeolite granules from Jinyun, China) was evaluated and compared with Quikclot in a lethal rabbit model of complex groin injury. [...] Read more.

Quikclot has been used many years for treating external hemorrhage in the battle field. In this study, the hemostatic performance of NZG-JY (natural zeolite granules from Jinyun, China) was evaluated and compared with Quikclot in a lethal rabbit model of complex groin injury. Fifty-six anesthetized rabbits were randomized to three different groups: (1) NZG-JY (n = 19); (2) Quikclot (n = 19); and (3) medical gauze (n = 18). Survival was recorded three hours after the application of the hemostatic agents. The wound healing properties of the survived animals (n = 4 for each group) were observed a week later. The clotting efficiency is 100% for the animals in the NZG-JY and the Quikclot group, while only 5.6% in the gauze group. The mortality in the NZG-JY group (21.0%) is significantly less than that in the Quikclot group (52.6%) and the gauze group (66.7%). A good healing property was achieved in all animals that survived in the NZG-JY group, while three quarters of the animals in the Quikclot group had serious necrotic tissue. NZG-JY significantly decreases the mortality in a lethal rabbit model of complex groin injury and demonstrates good healing properties. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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Review

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697 KiB

Open AccessReview

SBA-15 Mesoporous Silica as Catalytic Support for Hydrodesulfurization Catalysts—Review

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Rafael Huirache-Acuña

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Rufino Nava

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Carmen L. Peza-Ledesma

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Materials 2013, 6(9), 4139-4167; https://doi.org/10.3390/ma6094139 - 17 Sep 2013

Cited by 165 | Viewed by 16629

Abstract

SBA-15 is an interesting mesoporous silica material having highly ordered nanopores and a large surface area, which is widely employed as catalyst supports, absorbents, drug delivery materials, etc. Since it has a lack of functionality, heteroatoms and organic functional groups have been incorporated [...] Read more.

SBA-15 is an interesting mesoporous silica material having highly ordered nanopores and a large surface area, which is widely employed as catalyst supports, absorbents, drug delivery materials, etc. Since it has a lack of functionality, heteroatoms and organic functional groups have been incorporated by direct or post-synthesis methods in order to modify their functionality. The aim of this article is to review the state-of-the-art related to the use of SBA-15-based mesoporous systems as supports for hydrodesulfurization (HDS) catalysts. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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10294 KiB

Open AccessReview

A Review on the Synthesis and Applications of Mesostructured Transition Metal Phosphates

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Ronghe Lin

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Yunjie Ding

Materials 2013, 6(1), 217-243; https://doi.org/10.3390/ma6010217 - 15 Jan 2013

Cited by 80 | Viewed by 9527

Abstract

Considerable efforts have been devoted to extending the range of the elemental composition of mesoporous materials since the pioneering work of the M41S family of ordered mesoporous silica by Mobil researchers. The synthesis of transition metal-containing mesostructured materials with large surface area and [...] Read more.

Considerable efforts have been devoted to extending the range of the elemental composition of mesoporous materials since the pioneering work of the M41S family of ordered mesoporous silica by Mobil researchers. The synthesis of transition metal-containing mesostructured materials with large surface area and high porosity has drawn great attention for its potential applications in acid and redox catalysis, photocatalysis, proton conducting devices, environmental restoration and so on. Thus, various transition metals-containing mesoporous materials, including transition metal-substituted mesoporous silicates, mesostructured transition metal oxides and transition metal phosphates (TMP), have been documented in the literature. Among these, mesostructured TMP materials are less studied, but possess some unique features, partly because of the easy and facile functionalization of PO₄ and/or P–OH groups, rendering them interesting functional materials. This review first introduced the general synthesis strategies for manufacturing mesostructured TMP materials, as well as advantages and disadvantages of the respective method; then, we surveyed the ongoing developments of fabrication and application of the TMP materials in three groups on the basis of their components and application fields. Future perspectives on existing problems related to the present synthesis routes and further modifying of the functional groups for the purpose of tailoring special physical-chemical properties to meet wide application requirements were also provided in the last part. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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1985 KiB

Open AccessReview

A Review: Fundamental Aspects of Silicate Mesoporous Materials

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Zeid A. ALOthman

Materials 2012, 5(12), 2874-2902; https://doi.org/10.3390/ma5122874 - 17 Dec 2012

Cited by 1277 | Viewed by 34360

Abstract

Silicate mesoporous materials have received widespread interest because of their potential applications as supports for catalysis, separation, selective adsorption, novel functional materials, and use as hosts to confine guest molecules, due to their extremely high surface areas combined with large and uniform pore [...] Read more.

Silicate mesoporous materials have received widespread interest because of their potential applications as supports for catalysis, separation, selective adsorption, novel functional materials, and use as hosts to confine guest molecules, due to their extremely high surface areas combined with large and uniform pore sizes. Over time a constant demand has developed for larger pores with well-defined pore structures. Silicate materials, with well-defined pore sizes of about 2.0–10.0 nm, surpass the pore-size constraint (<2.0 nm) of microporous zeolites. They also possess extremely high surface areas (>700 m² g⁻¹) and narrow pore size distributions. Instead of using small organic molecules as templating compounds, as in the case of zeolites, long chain surfactant molecules were employed as the structure-directing agent during the synthesis of these highly ordered materials. The structure, composition, and pore size of these materials can be tailored during synthesis by variation of the reactant stoichiometry, the nature of the surfactant molecule, the auxiliary chemicals, the reaction conditions, or by post-synthesis functionalization techniques. This review focuses mainly on a concise overview of silicate mesoporous materials together with their applications. Perusal of the review will enable researchers to obtain succinct information about microporous and mesoporous materials. Full article

(This article belongs to the Special Issue Advances in Mesoporous Materials)

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