Fabrication and characterization of mesoporous borosilicate glasses with different boron contents

2007 ◽  
Vol 22 (7) ◽  
pp. 1834-1838 ◽  
Author(s):  
Tongping Xiu ◽  
Qian Liu ◽  
Jiacheng Wang
Keyword(s):  
Boric Acid ◽  
Self Assembly ◽  
Sol Gel ◽  
Sorption Isotherms ◽  
Mesoporous Structure ◽  
Borosilicate Glasses ◽  
Whole Process ◽  
Transmission Electron ◽  
Evaporation Induced Self Assembly ◽  
The Stability

A series of wormhole-like mesoporous borosilicate glasses (MBSGs) with different compositions has been prepared by a combination of surfactant templating, sol-gel methods, and evaporation-induced self-assembly processes. Small-angle x-ray diffraction, high-resolution transmission electron microscopy, and N2 sorption isotherms analysis showed that all the MBSGs prepared possess the mesoporous structure. However, the stability of the mesoporous structure is strongly affected by the boron contents. When boron content was increased, boric acid was found in the final product, and the mesoporous structure was partially degraded. The formation and loss of boric acid through the whole process may account for the partial collapse of the mesostructure.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Embedded Gadolinium Oxide

2011 ◽  
Vol 306-307 ◽  
pp. 1275-1279 ◽  
Author(s):  
Ning Qi Luo ◽  
Zhan Yun Huang ◽  
Ping Luo ◽  
Yuan Zhi Shao ◽  
Di Hu Chen
Keyword(s):  
Mesoporous Silica ◽  
Self Assembly ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Gadolinium Oxide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

We first synthesized gadolinium oxide (Gd2O3) by a modified “polyol” strategy and then embedded it into mesoporous silica by a simple self-assembly sol-gel reaction. Scanning electron microscope (SEM) results show that the samples have good sphericity and good dispersibility. The structure of mesoporous silica was characterized by transmission electron microscopy (TEM) and small-angle X-ray diffraction (SAXRD). Results show that the mesoporous structure has not been destroyed after gadolinium oxide imbedding. The ratio of gadolinium and silica was determined by the mean of energy dispersive spectroscopy (EDS).

scholarly journals Optical Properties of Sol-Gel Nb2O5Films with Tunable Porosity for Sensing Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Rosen Georgiev ◽  
Biliana Georgieva ◽  
Marina Vasileva ◽  
Petar Ivanov ◽  
Tsvetanka Babeva
Keyword(s):  
Self Assembly ◽  
Optical Constants ◽  
Sol Gel ◽  
Reflectance Spectra ◽  
Silicon Substrates ◽  
Selected Area Electron Diffraction ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Evaporation Induced Self Assembly

Thin Nb2O5films with tunable porosity are deposited by the sol-gel and evaporation induced self-assembly methods using organic template Pluronic PE6100 with different molar fractions with respect to NbCl5used as a precursor for synthesis of Nb sol. Surface morphology and structure of the films are studied by Transmission Electron Microscopy and Selected Area Electron Diffraction. The optical characterization of the films is carried out through reflectance spectra measurements of the films deposited on silicon substrates and theoretical modeling in order to obtain refractive index, extinction coefficient, and thickness of the films. The overall porosity of the films and the amount of adsorbed acetone vapors in the pores are quantified by means of Bruggeman effective medium approximation using already determined optical constants. The sensing properties of the samples are studied by measuring both the reflectance spectra and room-temperature photoluminescence spectra prior to and after exposure to acetone vapors and liquid, respectively. The potential of using the studied mesoporous Nb2O5films for chemooptical sensing is demonstrated and discussed.

scholarly journals Mesoporous MgTa2O6 thin films with enhanced photocatalytic activity: On the interplay between crystallinity and mesostructure

2012 ◽  
Vol 3 ◽  
pp. 123-133 ◽  
Author(s):  
Jin-Ming Wu ◽  
Igor Djerdj ◽  
Till von Graberg ◽  
Bernd M Smarsly
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Calcination Temperature ◽  
Self Assembly ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Ordered Mesoporous ◽  
Mesoporous Film ◽  
Evaporation Induced Self Assembly ◽  
Poly Ethylene

Ordered mesoporous, crystalline MgTa2O6 thin films with a mesoscopic nanoarchitecture were synthesized by evaporation-induced self-assembly (EISA) in combination with a sol–gel procedure. Utilization of novel templates, namely the block copolymers KLE (poly(ethylene-co-butylene)-b-poly(ethylene oxide)) and PIB6000 (CH3C(CH3)2(CH2C(CH3)2)107CH2C(CH3)2C6H4O(CH2CH2O)100H), was the key to achieving a stable ordered mesoporous structure even upon crystallization of MgTa2O6 within the mesopore walls. The effect of the calcination temperature on the ability of the mesoporous films to assist the photodegradation of rhodamine B in water was studied. As a result, two maxima in the photocatalytic activity were identified in the calcination temperature range of 550–850 °C, peaking at 700 °C and 790 °C, and the origin of this was investigated by using temperature-dependent X-ray scattering. Optimal activity was obtained when the mesoporous film was heated to 790 °C; at this temperature, crystallinity was significantly high, with MgTa2O6 nanocrystals of 1.6 nm in size (averaged over all reflections), and an ordered mesoporous structure was maintained. When considering the turnover frequency of such photocatalysts, the optimized activity of the present nanoarchitectured MgTa2O6 thin film was ca. four times that of analogous anatase TiO2 films with ordered mesopores. Our study demonstrated that high crystallinity and well-developed mesoporosity have to be achieved in order to optimize the physicochemical performance of mesoporous metal-oxide films.

scholarly journals Effect of boron incorporation on the bioactivity, structure, and mechanical properties of ordered mesoporous bioactive glasses

2020 ◽  
Vol 8 (7) ◽  
pp. 1456-1465 ◽  
Author(s):  
Leonie Deilmann ◽  
Oliver Winter ◽  
Bianca Cerrutti ◽  
Henrik Bradtmüller ◽  
Christopher Herzig ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Self Assembly ◽  
Sol Gel ◽  
Bioactive Glasses ◽  
Structure Directing Agent ◽  
Structural Investigations ◽  
Ordered Mesoporous ◽  
Evaporation Induced Self Assembly

B2O3 doped (0.5–15 mol%) ordered mesoporous bioactive glasses were synthesized via sol–gel based evaporation-induced self-assembly using P123 as a structure directing agent and characterized by biokinetic, mechanical and structural investigations.

SYNTHESIS OF ZnS:Mn/SILICA CORE/SHELL MICROSPHERES WITH A COMBINATION OF SOL–GEL AND SELF-TEMPLATING TECHNIQUES

NANO ◽  
2014 ◽  
Vol 09 (03) ◽  
pp. 1450028
Author(s):  
QING ZHANG
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Fluorescence Emission ◽  
Core Shell ◽  
Reaction Conditions ◽  
Whole Process ◽  
Transmission Electron ◽  
Novel Method ◽  
Nanosilica Particles

Core/shell microspheres with functional Mn -doped ZnS microspheres ( ZnS : Mn ) as core and with nanosilica particles as shell were prepared by a combination of sol–gel and self-templating techniques. The characteristic of this novel method was that the whole process required neither additional surfactant nor stabilizer, which exempted from removing the template and reduced reaction steps compared to the conventional process. The morphologies, structure and particle size distribution of the resulting ZnS : Mn / SiO 2 microspheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. Surface chemical composition and optical properties were determined with X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy, respectively. In addition, the effects of reaction conditions on the structure and morphologies were investigated. Experimental results indicated that the resulting ZnS : Mn / SiO 2 microspheres were perfectly spherical with distinct core/shell structures, and exhibited stronger fluorescence emission.

scholarly journals Ni-containing catalysts based on ordered mesoporous MgO–Al2O3for methane dry reforming

2018 ◽  
Vol 5 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Svetlana Pavlova ◽  
Yuliya Fedorova ◽  
Arkadii Ishchenko ◽  
Maxim Melgunov ◽  
Elena Melgunova ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mesoporous Structure ◽  
Dry Reforming ◽  
One Pot ◽  
Methane Dry Reforming ◽  
Pluronic P123 ◽  
Ordered Mesoporous ◽  
Evaporation Induced Self Assembly ◽  
The One ◽  
Adsorption Desorption

Abstract The ordered mesoporous Mg- and Ni-Mg-alumina samples of general formula xwt%Mg-Al2O3 and ywt%Nixwt% Mg-Al2O3(x, y = 5, 10 % wt) have been prepared by the one-pot evaporation induced self-assembly (EISA) method using Pluronic P123 as a template. The textural and structural properties of the prepared samples have been characterized by N2adsorption-desorption analysis, BET, XRD, TEM with EDX, HAADF-STEM, and H2-TPR. The samples calcined at 700°C had an ordered mesoporous structure with a SSA of 170-250 m2/g, a pore volume of 0.5-0.64 cm3/g and a narrow distribution of the pore size (mean 12-16 nm). For the catalysts prepared by the one-pot EISA method, the size of the metal Ni particles was in the range of 3-12 nm and was conditioned by their confinement in the mesopores and the interaction with MgO and Al2O3. Testing in methane dry reforming in the 15v.% CH4+ 15v.%CO2feed, with He balance, at 650-750°C and the contact time of 0.015 s has shown the higher activity and stability of the ordered mesoporous 10w%Ni- 10w%Mg-Al2O3catalysts prepared by the one-pot method as compared with the catalyst of the same composition obtained by impregnation.

Effect of Magnesium Coating Prior to Lithium Loading over SBA-15 for Stabilization of its Mesostructure

2014 ◽  
Vol 917 ◽  
pp. 3-9
Author(s):  
Muhammad Ayoub ◽  
Ahmad Zuhairi Abdullah
Keyword(s):  
Pore Size ◽  
Pore Volume ◽  
Mesoporous Material ◽  
Mesoporous Structure ◽  
Electron Microscopic ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
The Stability ◽  
Basic Strength

Mesoporous material SBA-15 was synthesized using P123 and TEMOS as the templates. Lithium in the form of LiOH was loaded over a previously prepared SBA-15. The basic strength of the prepared samples of SBA-15 was found to increase but the mesoporous structure was severely destroyed. The mesoporous structure of the prepared SBA-15 was retained after coating it with 30 wt. % magnesium prior to LiOH loading. The stability of mesoporous structure was strongly influenced by the extent of magnesium coating. It was also noted that this structure was also affected by LiOH loading and significantly destroyed structure when magnesium coating value exceeded 20 %. These samples were thoroughly characterized for their surface area, pore volume, pore size, basic strength, SAXRD patterns and transmission electron microscopic (TEM) analysis.

Preparation, Characterization, and Photocatalytic Performance of Bismuth and Boron Co-Doped Mesporous TiO2 by EISA Method

2014 ◽  
Vol 953-954 ◽  
pp. 1003-1007
Author(s):  
Yu Xiu Zhang ◽  
Li Yang ◽  
Dai Mei Chen ◽  
Shuang Deng ◽  
Ying Jie Shi
Keyword(s):  
Visible Light ◽  
Self Assembly ◽  
Photocatalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Assembly Method ◽  
Transmission Electron ◽  
Evaporation Induced Self Assembly ◽  
Crystallite Sizes ◽  
Mesoporous Structures

Abstract. The large-pore mesoporous Bi-B-TiO2 nanoparticles with the different Bi/Ti rations were prepared by EISA(evaporation-induced self-assembly) method. The prepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 absorption-desorption, ultraviolet visible light spectroscopy and photoluminescence spectroscopy technologies. The results revealed that all the samples are large aperture mesoporous structures. The crystallite sizes were in the range7-11nm, as confirmed by the results obtained from TEM images. The photodecomposition experiments showed that the photodegradation activity of Bi-B-doped TiO2 was higher than that of undoped TiO2 in degradation of 2, 4–dichlorophenol under visible light irradiation.

Synthesis of Three-Dimensionally Interconnected Hierarchical Meso/Mesoporous Tb3+ Doped Titania with Enhanced Photocatalytic Activity

2013 ◽  
Vol 275-277 ◽  
pp. 1755-1761
Author(s):  
Wei Yin ◽  
Lei Shi ◽  
Dan Hua Zhao ◽  
Xiu Lian Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Irradiation Condition ◽  
Sensitive Material ◽  
Transmission Electron ◽  
Ultrasonic Assisted ◽  
Width Distribution ◽  
Doped Titania ◽  
Adsorption Desorption

The precursor was prepared by cohydrolysis reactions of Ti(OC2H5)4and Tb(OC2H5)6around micelles of cetyltrimethylammonium bromide processed by ultrasonic before the cohydrolysis reactions. After calcined the precursor, Terbium doped anatase with a three-dimensionally interconnected hierarchical meso/mesoporous structure had been successfully prepared using an ultrasonic-assisted routine of sol-gel. The three-dimensionally interconnected hierarchical meso/mesoporous structure of the prepared material was proved by high resolution transmission electron microscopy and N2adsorption-desorption analysis. The material prepared displays a pore width distribution curve of single peak at 17.8 nm and displays a range from 6 nm to 42 nm, and possesses a BET area of 105 m2/g and a porosity of 0.65 cm3/g. The results of XPS analysis show that Ti exists in the Ti4+form and Ti-O-Tb/H and Ti-O-Ti bonds exist in the surface of the mesoporous material prepared. The terbium-doped sensitive material prepared possessing a three-dimensionally interconnected hierarchical meso/mesoporous structure is conducive mass-transferring and light-harvesting, and shows that a photocatalytic activity for phenol is about 4.9 times than that of commercial P25 titania under a very weak UV-Vis irradiation condition.

Hierarchical Macro-Mesoporous Silica Monolith

2004 ◽  
Vol 847 ◽  
Author(s):  
Tomohiko Amatani ◽  
Kazuki Nakanishi ◽  
Kazuyuki Hirao ◽  
Tetsuya Kodaira
Keyword(s):  
Self Assembly ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Silica Gels ◽  
Polymerization Reaction ◽  
Structure Directing Agent ◽  
Swelling Agent ◽  
Pure Silica ◽  
Inorganic Species ◽  
Hexagonal Arrays

ABSTRACTMonolithic pure silica gels with hierarchical macro-mesoporous structure have been synthesized via spontaneous sol-gel process from silicon alkoxide using a structure-directing agent and a micelle-swelling agent. Monolithic body with well-defined co-continuous macropores is a result of concurrent phase separation and sol-gel transition induced by the polymerization reaction, whereas the mesopores are templated by the cooperative self-assembly of inorganic species, a structure-directing agent and a micelle-swelling agent. The following removal of surfactants by heat-treatment gives silica gels with hierarchical and fully accessible pores in discrete size ranges of micrometers and nanometers. The highly ordered 2D-hexagonal arrays of mesopores have been confirmed by X-ray diffraction measurements and FE-SEM observations. Furthermore, by further additions of the micelle-swelling agent, the mesostructural transition from well-ordered 2D-hexagonal arrays to mesostructured cellular foams (MCF) have been induced accompanied by minor modifications of the micrometer-range structure.

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