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Author Collart, O.; Cool, P.; van der Voort, P.; Meynen, V.; Vansant, E.F.; Houthoofd, K.J.; Grobet, P.J.; Lebedev, O.I.; Van Tendeloo, G.
Title Aluminum incorporation into MCM-48 toward the creation of Brønsted acidity Type A1 Journal article
Year 2004 Publication The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical Abbreviated Journal J Phys Chem B
Volume 108 Issue Pages 13905-13912
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000224164000003 Publication Date 2004-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1520-6106;1520-5207; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.177 Times cited 13 Open Access
Notes Fwo; Iuap P5/01 Approved Most recent IF: 3.177; 2004 IF: 3.834
Call Number (up) UA @ lucian @ c:irua:49014 Serial 92
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Author Meynen, V.; Cool, P.; Vansant, E.F.; Kortunov, P.; Grinberg, F.; Kärger, J.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.
Title Deposition of vanadium silicalite-1 nanoparticles on SBA-15 materials: structural and transport characteristics of SBA-VS-15 Type A1 Journal article
Year 2007 Publication Microporous and mesoporous materials Abbreviated Journal Micropor Mesopor Mat
Volume 99 Issue 1/2 Pages 14-22
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000243845200003 Publication Date 2006-10-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 23 Open Access
Notes FWO; GOA; Inside-Pores NoE (FP-EU) Approved Most recent IF: 3.615; 2007 IF: 2.210
Call Number (up) UA @ lucian @ c:irua:61567 Serial 647
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Author Meynen, V.; Busuioc, A.M.; Beyers, E.; Cool, P.; Vansant, E.F.; Bilba, N.; Mertens, M.; Lebedev, O.; Van Tendeloo, G.
Title Nanodesign of combined micro- and mesoporous materials for specific applications in adsorption and catalysis Type H3 Book chapter
Year 2007 Publication Abbreviated Journal
Volume Issue Pages
Keywords H3 Book chapter; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract
Address
Corporate Author Thesis
Publisher Nova Place of Publication New York Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (up) UA @ lucian @ c:irua:63126 Serial 2251
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Author Stevens, W.J.J.; Meynen, V.; Bruijn, E.; Lebedev, O.I.; Van Tendeloo, G.; Cool, P.; Vansant, E.F.
Title Mesoporous material formed by acidic hydrothermal assembly of silicalite-1 precursor nanoparticles in the absence of meso-templates Type A1 Journal article
Year 2008 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 110 Issue 1 Pages 77-85
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000254056200010 Publication Date 2007-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 21 Open Access
Notes Fwo; Crp; Inside-Pores Approved Most recent IF: 3.615; 2008 IF: 2.555
Call Number (up) UA @ lucian @ c:irua:68229 Serial 1998
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Author de Witte, K.; Meynen, V.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Sepúlveda-Escribano, A.; Rodríguez-Reinoso, F.; Vansant, E.F.; Cool, P.
Title Multi-step loading of titania on mesoporous silica: influence of the morphology and the porosity on the catalytic degradation of aqueous pollutants and VOC's Type A1 Journal article
Year 2008 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 84 Issue 1/2 Pages 125-132
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Titania nanoparticles have been deposited on inert porous silica supports with high specific surface area. These materials have potential applications in paint and textile industry as the titania particles selectively deposited on the inner surface of the silica supports act as a photocatalyst. The inert external surface is necessary to avoid photodegradation of the textile material or the paint components. The photocatalytic activity of the catalysts has been evaluated with two catalytic setups. One setup in aqueous phase, for the degradation of dyes such as rhodamine-6G, is commonly used. The second setup is a continuous flow gaseous phase setup which was used for the mineralization of ethanol as a representative volatile organic compound (VOC). The influence of the porosity and the morphology of the silica supports on the photocatalytic activity are discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000260728300017 Publication Date 2008-04-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-3373; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.446 Times cited 24 Open Access
Notes Iwt 30916; Fwo Approved Most recent IF: 9.446; 2008 IF: 4.853
Call Number (up) UA @ lucian @ c:irua:68279 Serial 2213
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Author de Witte, K.; Busuioc, A.M.; Meynen, V.; Mertens, M.; Bilba, N.; Van Tendeloo, G.; Cool, P.; Vansant, E.F.
Title Influence of the synthesis parameters of TiO2-SBA-15 materials on the adsorption and photodegradation of rhodamine-6G Type A1 Journal article
Year 2008 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 110 Issue 1 Pages 100-110
Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000254056200013 Publication Date 2007-10-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 54 Open Access
Notes Approved Most recent IF: 3.615; 2008 IF: 2.555
Call Number (up) UA @ lucian @ c:irua:68280 Serial 1654
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Author Ribbens, S.; Meynen, V.; Van Tendeloo, G.; Ke, X.; Mertens, M.; Maes, B.U.W.; Cool, P.; Vansant, E.F.
Title Development of photocatalytic efficient Ti-based nanotubes and nanoribbons by conventional and microwave assisted synthesis strategies Type A1 Journal article
Year 2008 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 114 Issue 1/3 Pages 401-409
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Abstract Titanate nanotubes were prepared via a hydrothermal treatment of TiO2 powders (Riedel De Haen) in a basic solution. Morphology and structure of the prepared samples were characterized by high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), XRD, FT-Raman spectroscopy, nitrogen sorption and DSC. The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine 6G. Trititanate nanotubes (TTNT) with inner pore diameters between 4 and 4.2 nm and surface areas up till 360 m(2)/g could be synthesized. The synthesis route was modified by introduction of a calcination step, by applying a lower hydrothermal temperature and microwave irradiation in order to increase the photocatalytic activity of the porous photoactive nanotubular materials. Calcination and a softer hydrothermal treatment led to the formation of anatase without affecting the surface area and nanotubular shape of the samples. In this way, the photocatalytic activity of the original trititanate nanotubes could be significantly increased. By making use of microwave assisted synthesis, the photocatalytic activity call also be increased due to the presence of anatase. However, by applying microwave synthesis, a different structure was obtained, nanoribbons (NR) instead of nanotubcs, resulting in a decrease in surface area and porosity.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000258432100040 Publication Date 2008-02-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 47 Open Access
Notes Fwo; Crp (Ua) Approved Most recent IF: 3.615; 2008 IF: 2.555
Call Number (up) UA @ lucian @ c:irua:69696 Serial 683
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Author Liu, S.; Lebedev, O.I.; Mertens, M.; Meynen, V.; Cool, P.; Van Tendeloo, G.; Vansant, E.F.
Title The merging of silica-surfactant microspheres under hydrothermal conditions Type A1 Journal article
Year 2008 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 116 Issue Pages 141-146
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Post-synthesis hydrothermal treatments have been used to improve the quality of MCM-41 materials. In our latest work, merging of surfactant-containing silica microspheres during the hydrothermal treatments was observed. Mechanistic insights and the different stages that are involved in the merging process can be summarized as follows. First, the surfaces of the starting microspheres open up due to the dissolution of silica. Then the dissolved silica species provide mass source for the formation of particle necks connecting two neighboring microspheres. Gradually, surfaces of the starting microspheres are flattened to meet the needs of further growth of the necks. Finally, some chain-like highly-ordered mesoporous structures up to several micrometers are formed. The observed merging of the surfactant-containing microspheres is a re-assembling process, which is under the control of electrostatic force between the dissolved silica species and the surfactant cations. The occluded surfactant cations in the precursor spheres play important roles in the merging process.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000261133600021 Publication Date 2008-04-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 5 Open Access
Notes Fwo; Goa Approved Most recent IF: 3.615; 2008 IF: 2.555
Call Number (up) UA @ lucian @ c:irua:72021 Serial 1997
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Author van Oers, C.J.; Stevens, W.J.J.; Bruijn, E.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Meynen, V.; Cool, P.
Title Formation of a combined micro- and mesoporous material using zeolite Beta nanoparticles Type A1 Journal article
Year 2009 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 120 Issue 1/2 Pages 29-34
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Composite micro- and mesoporous materials are synthesized using zeolite Beta nanoparticles without the need for a structure directing agent to form the mesopores. This leads to important ecological and economical advantages. The influence of the way of cooling the aged nanoparticles solution on the formation of the composite materials has been studied. The materials have been characterized towards porosity by N2-sorption, towards zeolitic properties by TGA, DRIFT, XRD and TEM, towards aluminium content by EPMA. All prepared structures possess zeolitic properties. However, the method of cooling down of the aged seeds leads to differences in the porosity and intensity of the zeolitic characteristics.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000264619200006 Publication Date 2008-09-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 42 Open Access
Notes Crp; Sfr Ua Approved Most recent IF: 3.615; 2009 IF: 2.652
Call Number (up) UA @ lucian @ c:irua:74950 Serial 1254
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Author Smeulders, G.; Meynen, V.; van Baelen, G.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Maes, B.U.W.; Cool, P.
Title Rapid microwave-assisted synthesis of benzene bridged periodic mesoporous organosilicas Type A1 Journal article
Year 2009 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 19 Issue 19 Pages 3042-3048
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Abstract Following extended use in organic chemistry, microwave-assisted synthesis is gaining more importance in the field of inorganic chemistry, especially for the synthesis of nanoporous materials. It offers some major advantages such as a significant shortening of the synthesis time and an improved promotion of nucleation. In the research here reported, microwave technology is applied for the synthesis of benzene bridged PMOs (periodic mesoporous organosilicas). PMOs are one of the latest innovations in the field of hybrid ordered mesoporous materials and have attracted much attention because of their feasibility in electronics, catalysis, separation and sorption applications. The different synthesis steps (stirring, aging and extraction) of the classical PMO synthesis are replaced by microwave-assisted synthesis steps. The characteristics of the as-synthesized materials are evaluated by X-ray diffraction, N2-sorption, thermogravimetric analysis, scanning- and transmission electron microscopy. The microwave-assisted synthesis drastically reduces the synthesis time by more than 40 hours without any loss in structural properties, such as mesoscale and molecular ordering. The porosity of the PMO materials has even been improved by more than 25%. Moreover, the number of handling/transfer steps and amounts of chemicals and waste are drastically reduced. The study also shows that there is a clear time (1 to 3 hours) and temperature frame (373 K to 403 K) wherein synthesis of benzene bridged PMO is optimal. In conclusion, the microwave-assisted synthesis pathway allows an improved material to be obtained in a more economical way i.e. a much shorter time with fewer chemicals and less waste.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000265919300024 Publication Date 2009-03-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 20 Open Access
Notes Fwo; Iwt Approved Most recent IF: NA
Call Number (up) UA @ lucian @ c:irua:76844 Serial 2810
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Author Beyers, E.; Biermans, E.; Ribbens, S.; de Witte, K.; Mertens, M.; Meynen, V.; Bals, S.; Van Tendeloo, G.; Vansant, E.F.; Cool, P.
Title Combined TiO2/SiO2 mesoporous photocatalysts with location and phase controllable TiO2 nanoparticles Type A1 Journal article
Year 2009 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 88 Issue 3/4 Pages 515-524
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Combined TiO2/SiO2 mesoporous materials were prepared by deposition of TiO2 nanoparticles synthesised via the acid-catalysed solgel method. In the first synthesis step a titania solution is prepared, by dissolving titaniumtetraisopropoxide in nitric acid. The influences of the initial titaniumtetraisopropoxide concentration and the temperature of dissolving on the final structural properties were investigated. In the second step of the synthesis, the titania nanoparticles were deposited on a silica support. Here, the influence of the temperature during deposition was studied. The depositions were carried out on two different mesoporous silica supports, SBA-15 and MCF, leading to substantial differences in the catalytic and structural properties. The samples were analysed with N2-sorption, X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) to obtain structural information, determining the amount of titania, the crystal phase and the location of the titania particles on the mesoporous material (inside or outside the mesoporous channels). The structural differences of the support strongly determine the location of the nanoparticles and the subsequent photocatalytic activity towards the degradation of rhodamine 6G in aqueous solution under UV irradiation.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000266513400032 Publication Date 2008-10-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-3373; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.446 Times cited 69 Open Access
Notes Goa-Bof; Fwo Approved Most recent IF: 9.446; 2009 IF: 5.252
Call Number (up) UA @ lucian @ c:irua:77150 Serial 403
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Author Vernimmen, J.; Guidotti, M.; Silvestre-Albero, J.; Jardim, E.O.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Psaro, R.; Rodríguez-Reinoso, F.; Meynen, V.; Cool, P.
Title Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene Type A1 Journal article
Year 2011 Publication Langmuir: the ACS journal of surfaces and colloids Abbreviated Journal Langmuir
Volume 27 Issue 7 Pages 3618-3625
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000288970900054 Publication Date 2011-02-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0743-7463;1520-5827; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.833 Times cited 19 Open Access
Notes Approved Most recent IF: 3.833; 2011 IF: 4.186
Call Number (up) UA @ lucian @ c:irua:88366 Serial 1557
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Author Vernimmen, J.; Meynen, V.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Cool, P.
Title Formation of a Ti-siliceous trimodal material with macroholes, mesopores and zeolitic features via a one-pot templating synthesis Type A1 Journal article
Year 2012 Publication Journal of porous materials Abbreviated Journal J Porous Mat
Volume 19 Issue 2 Pages 153-160
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Based on a facile one-pot templating synthesis, using a TS-1 zeolite recipe whereby part of the zeolite structure directing agent is replaced by a mesopore templating agent, a trimodal material is formed. The resulting meso-TSM material combines mesoporosity (Ti-MCM-41) with zeolitic features (TS-1) and a unique sheet-like morphology with uniform macroporous voids (macroholes). Moreover, the macrohole formation, mesoporosity and zeolitic properties of the meso-TSM material can be controlled in a straightforward way by adjusting the length of the hydrothermal treatment. This newly developed material may imply great potential for catalytic redox applications and diffusion limitated processes because of its highly tunable character in all three dimensions (micro-, meso- and macroporous scale).
Address
Corporate Author Thesis
Publisher Kluwer Academic Place of Publication Boston, Mass. Editor
Language Wos 000301187600002 Publication Date 2011-03-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1380-2224;1573-4854; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.624 Times cited 2 Open Access
Notes Fwo; Goa Approved Most recent IF: 1.624; 2012 IF: 1.348
Call Number (up) UA @ lucian @ c:irua:88367 Serial 1257
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Author Vernimmen, J.; Meynen, V.; Herregods, S.J.F.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Cool, P.
Title New insights in the formation of combined zeolitic/mesoporous materials by using a one-pot templating synthesis Type A1 Journal article
Year 2011 Publication European journal of inorganic chemistry Abbreviated Journal Eur J Inorg Chem
Volume Issue 27 Pages 4234-4240
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Zeolitic growth is often absent or occurs in separate phases when synthetic strategies based on the combination of zeolite templates and mesopore templating agents are applied. In this work, zeolitic growth and mesopore formation have been investigated at different temperatures by applying a one-pot templating approach, based on a TS-1 zeolite synthesis whereby part of the microtemplate (tetrapropylammonium hydroxide, TPAOH) is replaced by a mesotemplate (hexadecyltrimethylammonium bromide, CTMABr). Moreover, the synthesis duration and the molar ratio of the microtemplate/mesotemplate have also been studied. The different syntheses clearly show the inherent competitive mechanism between zeolitic growth and mesopore formation. These insights have led to the conclusion that by following a one-pot templating strategy with standard, nonexotic commercial templates, i.e. CTMABr and TPAOH, it is not possible to develop a true hierarchical mesoporous zeolite, meaning a mesoporous siliceous material with highly crystalline zeolitic walls. The resultant materials are instead combined zeolitic/mesoporous composite structures with, however, highly tuneable and controllable porosity characteristics.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000296143500014 Publication Date 2011-08-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-1948; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.444 Times cited 7 Open Access
Notes Fwo Approved Most recent IF: 2.444; 2011 IF: 3.049
Call Number (up) UA @ lucian @ c:irua:91574 Serial 2315
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Author Smeulders, G.; van Oers, C.; Van Havenbergh, K.; Houthoofd, K.; Mertens, M.; Martens, J.A.; Bals, S.; Maes, B.U.W.; Meynen, V.; Cool, P.
Title Smart heating profiles for the synthesis of benzene bridged periodic mesoporous organosilicas Type A1 Journal article
Year 2011 Publication Chemical engineering journal Abbreviated Journal Chem Eng J
Volume 175 Issue Pages 585-591
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Abstract In this study the effects of the heating rate and heating time on the formation of crystal-like benzene bridged periodic mesoporous organosilicas (PMOs) are investigated. The time needed to heat up an autoclave during the hydrothermal treatment has shown to be crucial in the synthesis of PMOs, while the total duration of heating gave rise to only minor differences. By choosing a smart heating profile, superior PMO materials can be obtained in a short time. Different heating profiles in a range from one minute to one hour are adopted by microwave equipment and compared with conventional heating methods. The heating rate has a large influence on the porosity characteristics and the uniformity of the obtained particles. Moreover, two new alternative synthetic strategies to adopt the smart heating profile are presented, in order to give some possible solutions for the expensive microwave equipment.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000297875900069 Publication Date 2011-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited 7 Open Access
Notes Fwo; Goa-Bof Approved Most recent IF: 6.216; 2011 IF: 3.461
Call Number (up) UA @ lucian @ c:irua:93630 Serial 3044
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Author Ribbens, S.; Beyers, E.; Schellens, K.; Mertens, M.; Ke, X.; Bals, S.; Van Tendeloo, G.; Meynen, V.; Cool, P.
Title Systematic evaluation of thermal and mechanical stability of different commercial and synthetic photocatalysts in relation to their photocatalytic activity Type A1 Journal article
Year 2012 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 156 Issue Pages 62-72
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract The effect of thermal treatment and mechanical stress on the structural and photocatalytic properties of eight different (synthetic and commercial) photocatalysts has been thoroughly investigated. Different mesoporous Ti-based materials were prepared via surfactant based synthesis routes (e.g. Pluronic 123, CTMABr = Cetyltrimethylammonium bromide) or via template-free synthesis routes (e.g. trititanate nanotubes). Also, the stabilizing effect of the NaOH/NH4OH post-treatment on the templated mesoporous materials and their photocatalytic activity was investigated. Furthermore, the thermal and mechanical properties of commercially available titanium dioxides such as P25 Evonik® and Millenium PC500® were studied. The various photocatalysts were analyzed with N2-sorption, X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) to obtain information concerning the specific surface area, pore volume, crystal structure, morphology, phase transitions, etc. In general, results show that the NaOH post-treatment leads to an increased control of the crystallization process during calcination resulting in a higher thermal stability, but at the same time diminishes the photocatalytic activity. Mesoporous materials in which pre-synthesized nanoparticles are used as titania source have the best mechanical stability whereas the mechanical stability of the nanotubes is the most limited. At increased temperatures and pressures, the tested commercial titanium dioxides lose their superior photocatalytic activity caused by a decreased accessibility of the active sites. The observed changes in adsorption capacities and photocatalytic activities cannot be assigned to one single phenomenon. In this respect, it shows the need to define a general/standard method to compare different photocatalysts. Furthermore, it is shown that the photocatalytic properties do not necessarily deteriorate under thermal stress, but can be improved due to crystallization, even though the initial material is (partially) destroyed. It is shown that the usefulness of a specific type of photocatalyst strongly depends on the application and the temperature/pressure to which it needs to resist.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000303625200010 Publication Date 2012-02-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 8 Open Access
Notes Fwo Approved Most recent IF: 3.615; 2012 IF: 3.365
Call Number (up) UA @ lucian @ c:irua:96910 Serial 3466
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