References of "Microporous & Mesoporous Materials"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailHighly dispersed iron xerogel catalysts for p-nitrophenol degradation by photo-Fenton effects
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Zubiaur, Anthony ULg et al

in Microporous & Mesoporous Materials (2014), 197

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ... [more ▼]

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions. The EDAS/TEOS ratio strongly influences the texture of xerogel catalysts. The specific surface area and the micro- and mesoporous volume increase with this ratio. It seems that EDAS plays a nucleating agent role for silica particles and allows to anchor Fe-based moieties inside the silica network. Iron oxide nanoparticles of diameter 1-1.5 nm and Fe3+ ions result, encapsulated in silica particles with sizes of about 10-30 nm in diameter. The iron species was determined by Mössbauer spectroscopy and magnetometry measurements and only Fe3+ species were observed in xerogel catalysts. The Fenton and photo-Fenton effect of these catalysts were evaluated on the degradation of p-nitrophenol in aqueous media under different conditions. Results show that in the presence of H2O2, iron xerogel catalysts present a photo-Fenton effect, reaching 99 % of degradation after 24 h. [less ▲]

Detailed reference viewed: 25 (8 ULg)
Full Text
Peer Reviewed
See detailCharacterization of multi-walled carbon nanotube dispersion in resorcinol-formaldehyde aerogel
Haghgoo, Majid; Yousefi, Ali Akbar; Zohouriaan Mehr, Mohammad Jalal et al

in Microporous & Mesoporous Materials (2014), 184

Detailed reference viewed: 14 (1 ULg)
Full Text
Peer Reviewed
See detailRapid aqueous synthesis of ordered mesoporous carbons: Investigation of synthesis variables and application as anode materials for Li-ion batteries
Léonard, Alexandre ULg; Gommes, Cédric ULg; Piedboeuf, Marie-Laure ULg et al

in Microporous & Mesoporous Materials (2014), 195

Ordered mesoporous carbons (OMC) were synthesized via a direct templating pathway by a synthesis route that features short duration, moderate temperature and aqueous media. Resorcinol was used as carbon ... [more ▼]

Ordered mesoporous carbons (OMC) were synthesized via a direct templating pathway by a synthesis route that features short duration, moderate temperature and aqueous media. Resorcinol was used as carbon precursor and hexamethylenetetramine as a source of formaldehyde and ammonia to respectively cross-link the framework and regulate the pH. The temperature of the heat treatment leading to the formation of the solid polymer was shown to have a strong influence on the structural and textural parameters. In particular, moderate temperatures led to the coexistence of differently-sized entangled hexagonal mesostructures, whereas the higher temperatures led to a sharp decrease in the mesopore volume. The performance of these materials as anode materials for Li-ion batteries has been investigated in detail. Although these OMC show reversible capacities similar to those reported for hard carbons, their long-term cycling remains very stable for over 100 cycles of charge/discharge. The optimization of the reported short preparation pathway offers new possibilities regarding the application of ordered mesoporous carbons in various fields, such as energy storage, sorption and heterogeneous catalysis [less ▲]

Detailed reference viewed: 24 (6 ULg)
Full Text
Peer Reviewed
See detailLithium transition metal (Ti, Nb, V) oxide mesoporous thin films: contrasting results when attempting direct synthesis by evaporation-induced self assembly
Caes, Sébastien ULg; Malherbe, Cédric ULg; Krins, Natacha ULg et al

in Microporous & Mesoporous Materials (2013), 172

This work investigates the possibility to prepare mesoporous thin films of Li-Ti, Li-Nb, Li-Nb-V and Li-V oxides through a direct sol-gel EISA route by dissolving a lithium salt in the precursor solution ... [more ▼]

This work investigates the possibility to prepare mesoporous thin films of Li-Ti, Li-Nb, Li-Nb-V and Li-V oxides through a direct sol-gel EISA route by dissolving a lithium salt in the precursor solution. Experimental conditions involve a hydrolysis molar ratio H2O/TM ~10 (TM = Ti,Nb,V) and the common Pluronic structuring agent P123 (EO20-PO70-EO20). Systematic formation of lithium-containing oxides as first-crystallizing phases points to a significant intermixture of lithium and transition metal ions in the inorganic network. In the case of Ti-based and Nb-based oxide films, addition of lithium to the precursor solution is compatible with the formation of amorphous mesoporous films at 350°C. On the contrary, addition of lithium has a detrimental effect on the notoriously difficult formation of vanadium-based mesostructured films: even when replacing half of the vanadium by niobium as a stabilizer, formation of mesostructured films has not been possible in the investigated range of experimental conditions. [less ▲]

Detailed reference viewed: 63 (33 ULg)
Full Text
Peer Reviewed
See detailCharacterization of H3+xPMo12 xVxO40 heteropolyacids supported on HMS mesoporous molecular sieve and their catalytic performance in propene oxidation
Benadji, Siham; Eloy, Pierre; Léonard, Alexandre ULg et al

in Microporous & Mesoporous Materials (2012), 154

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailTiO2 mesoporous thin films studied by Atmospheric Ellipsometric Porosimetry: A case of contamination
Dubreuil, Olivier ULg; Dewalque, Jennifer ULg; Chene, Grégoire ULg et al

in Microporous & Mesoporous Materials (2011), 147

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the ... [more ▼]

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the determination of the porosity of such films. After prolonged exposition to high-vacuum (6×10-6 mbar), the films porosity exhibits a degraded behavior during porosimetric measurements, indicating a vacuum-induced modification. The main effect resulting from such exposition to high-vacuum is a wet- tability modification of the films, resulting in an increase of the hydrophobic character of the TiO2 surface. This evolution induces non-correct results in porosimetric measurements due to the fact that the contact angle parameter needed to calculate the pore size distribution is highly different from the reference films. A surface contamination explains such modifications and a restoration of the films is obtained by using ultraviolet treatment. [less ▲]

Detailed reference viewed: 108 (38 ULg)
Full Text
Peer Reviewed
See detailEffects of additives and solvents on the gel formation rate and on the texture of P- and Si-doped TiO2 materials
Bodson, Céline ULg; Lambert, Stéphanie ULg; Alié, Christelle ULg et al

in Microporous & Mesoporous Materials (2010), 134

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The ... [more ▼]

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The mechanisms of formation of the gels have been studied before gelation by liquid NMR spectroscopy and connected to their structure after drying analyzed by Raman spectroscopy, solid state NMR and N2 adsorption/desorption. The effects of the additives and solvents on the gel formation rate and on the texture of the xerogel have been addressed. [less ▲]

Detailed reference viewed: 91 (30 ULg)
Full Text
Peer Reviewed
See detailPreparation and characterization of HMS supported 11-molybdo-vanado-phosphoric acid for selective oxidation of propylene
Benadji, S.; Eloy, P.; Léonard, Alexandre ULg et al

in Microporous & Mesoporous Materials (2010), 130(1-3), 103-114

The preparation of Keggin-type phosphovanadomolybdic acid H4PMo11VO40 (PMo11V) supported on a hexagonal mesoporous silicate (HMS) material was performed via three different methods: dry impregnation, wet ... [more ▼]

The preparation of Keggin-type phosphovanadomolybdic acid H4PMo11VO40 (PMo11V) supported on a hexagonal mesoporous silicate (HMS) material was performed via three different methods: dry impregnation, wet impregnation and mechanical mixing. The state of the heteropolyacid (HPA) on the siliceous surface and the integrity of the support were characterized by several physico-chemical techniques: elemental analysis, X-ray diffraction, transmission and diffuse reflectance (DR) FT-IR study of the framework vibrations, Raman and X-ray photoelectron spectroscopies, nitrogen physisorption, thermal analysis (TG-DTA) and scanning electron microscopy (SEM). The catalytic performance of supported materials was compared to that of the bulk H4PMo11VO40 in the selective oxidation of propylene by molecular oxygen in the temperature range of 200-400 °C. The physico-chemical characterization of the supported HPA showed mainly that the primary Keggin structure is intact and that a good dispersion of the heteropolyacid on the HMS surface is obtained when the impregnation methods are used. In the case of mechanical mixture, the dispersion of heteropolyacid clusters is not homogeneous. The surface area of HMS decreased when the HPA was added. The impregnation methods lead to mesopores with uniform size of approximatively 3.2 nm in diameter. The TG-DTA showed that the supported HPAs obtained by the impregnation methods have a higher thermal stability than that of bulk HPA. The catalytic results showed that H4PMo11VO40/HMS are more active than the bulk H4PMo11VO40 and lead to oxygenated compounds formation (acrolein, acetaldehyde and acetic acid), whereas the bulk HPA only leads to the formation of COx. © 2009 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 23 (0 ULg)
Full Text
Peer Reviewed
See detailControl of the porosity of anatase thin films prepared by EISA: Influence of thickness and heat treatment
Henrist, Catherine ULg; Dewalque, Jennifer ULg; Mathis, François ULg et al

in Microporous & Mesoporous Materials (2009), 117

Mesoporous anatase thin films were prepared by the evaporation-induced self-assembly process. This paper reports a study of the influence of several physical parameters on the long-range ordering of the ... [more ▼]

Mesoporous anatase thin films were prepared by the evaporation-induced self-assembly process. This paper reports a study of the influence of several physical parameters on the long-range ordering of the mesopores. A preliminary study was done to set the best humidity conditions during dip-coating and ageing of the films. The withdrawal speed, already known to modify the thickness of the deposited film, was shown to exert a strong influence on the percentage of porosity. This was studied by step profilometry combined with Rutherford backscattered spectrometry (RBS). In parallel, small angle X-ray scattering (SAXS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and RBS were used to tune the precise thermal treatment applied to the so-obtained films, in order to preserve the porous mesostructure and promote the nanocrystallization of anatase TiO2. [less ▲]

Detailed reference viewed: 119 (50 ULg)
Full Text
Peer Reviewed
See detailWater desorption from resorcinol-formaldehyde hydrogels and adsorption in the resulting xerogels
Escalona, Ivonne; Gommes, Cédric ULg; Job, Nathalie ULg et al

in Microporous & Mesoporous Materials (2009), 117

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various ... [more ▼]

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various temperatures. Isotherms obtained from samples synthesized at various pH are compared. Two different mechanisms are involved in RF hydrogels water desorption. At large relative humidity the capillary tension resulting from water removal induces a macroscopic shrinkage of the gel, whereas at low humidity water is evaporated with no network deformation. These two mechanisms are analyzed using a plastic deformation model and the Guggenheim-Anderson-de Boer (GAB) model, respectively. Adsorption isotherms of RF xerogels are analyzed using the GAB model. [less ▲]

Detailed reference viewed: 63 (10 ULg)
Full Text
Peer Reviewed
See detailAg-and SiO2-doped porous TiO2 with enhanced thermal stability
Braconnier, Benoît ULg; Páez Martínez, Carlos ULg; Lambert, Stéphanie ULg et al

in Microporous & Mesoporous Materials (2009), 122

Detailed reference viewed: 93 (39 ULg)
Full Text
Peer Reviewed
See detailTailor-made morphologies for Pd/SiO2 catalysts through sol-gel process with various silylated ligands
Lambert, Stéphanie ULg; Tran, Kim Yên; Arrachart, Guilhem et al

in Microporous & Mesoporous Materials (2008), 115

Detailed reference viewed: 22 (6 ULg)
Full Text
Peer Reviewed
See detailTailoring the textural properties of activated carbon xerogels by chemical activation with KOH
Zubizarreta, Leire; Arenillas, Ana; Pirard, Jean-Paul ULg et al

in Microporous & Mesoporous Materials (2008), 115(3), 480-490

Resorcinol-formaldehyde xerogels synthesised with different resorcinol/sodium carbonate molar ratios were chemically activated either after drying or after drying and pyrolysis, using potassium hydroxide ... [more ▼]

Resorcinol-formaldehyde xerogels synthesised with different resorcinol/sodium carbonate molar ratios were chemically activated either after drying or after drying and pyrolysis, using potassium hydroxide. It was found that organic (i.e. dried) and carbon (i.e. pyrolysed) xerogels behave differently when subjected to chemical activation. In the case of carbon xerogels, the increase in the microporosity takes place without any significant modification to the meso/macroporosity formed during the synthesis step, leading to micromesoporous or micro-macroporous materials with a larger micropore volume. Furthermore, control of the microporosity is possible because its development depends on the amount of KOH used. However, when organic xerogels are activated, mainly microporous materials with BET specific surface areas of up to 2000 m(2) g(-1) are obtained, there hardly remaining any of the meso/macroporosity formed during the gel synthesis. Thus, the combination of different synthesis conditions and chemical activation with potassium hydroxide allows the textural properties of carbon xerogels to be tailored at both micropore and meso/macropore levels. (c) 2008 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 60 (1 ULg)
Full Text
Peer Reviewed
See detailChemistry of silica at different concentrations of non-ionic surfactant solutions: Effect of pH of the synthesis gel on the preparation of mesoporous silicas
Léonard, Alexandre ULg; Blin, J. L.; Jacobs, P. A. et al

in Microporous & Mesoporous Materials (2003), 63(1-3), 59-73

Ordered and disordered mesoporous silicas have been synthesized through an assembly of non-ionic decaoxyethylene cetyl ether [C 16(EO) 10] and a tetramethoxysilane silica source by variation of the pH ... [more ▼]

Ordered and disordered mesoporous silicas have been synthesized through an assembly of non-ionic decaoxyethylene cetyl ether [C 16(EO) 10] and a tetramethoxysilane silica source by variation of the pH value of the synthesis gel. The structure, texture and morphology of the mesoporous silicas, synthesized with concentrated and diluted surfactant solutions, have been discussed from the perspective of silica's chemistry upon a variation of pH values of the synthesis gel (micellar solution). With concentrated surfactant solutions (50 wt%), disordered compounds are obtained in a range of pH from 2.0 to 7.0 (micellar solution). As the pH increases, however, the pore size distributions (PSD) become broader and bimodality appears due to the micelle-templated silica (MTS) mesopores and openings arising from silica dissolution-reprecipitation processes. Also, the MTS pores expand due to a change in conformation of the surfactant hydrophilic head upon pH increase. On the other hand, diluted surfactant solutions (10 wt%) lead to ordered materials in a pH range from 2.0 to 7.0 (synthesis gel). The PSD remain very narrow but interparticular porosity appears and the morphologies undergo deep changes from toroids, gyroids and ropes to aggregates of very small particles with increasing pH. © 2003 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 11 (1 ULg)