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Synthesis of Mesoporous Silica and their Use as Templates for Metal and Metal Oxide Nanoparticles
Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis covers the synthesis and characterization of two types of mesoporous silica, SBA-15 silica with two-dimensional hexagonal arrangement, and SBA-16 silica with three-dimensional cubic arrangement. The obtained mesoporous materials were then used as hard templates for synthesizing of different types of nanostructures.

In the first part, the effects of some synthesis parameters on the morphology and texture properties of the mesoporous silica have been studied. By varying the synthesis temperature solid spheres of SBA-16 with different sizes were synthesized and by additions of heptane as a swelling agent, SBA-16 in a hollow-sphere morphology with a large pore size was obtained. In the case of SBA-15, dispersed rods were synthesized in the presence of heptane and NH4F in a low-temperature synthesis. The length of the rods was varied by changing the concentration of HCl, and the pore size was tuned by changing the hydrothermal treatment time and temperature. Furthermore, the reaction time was decreased with a well-retained pore size and morphology. This work has resulted in SBA-15 rods with large pore sizes for this morphology.

In the second part, SBA-15 and SBA-16 silica were used to synthesize different nanostructured materials such as metal and metal oxide nanoparticles. In fact, most of the work in this part is focused on the use of mesoporous silica as hard templates for synthesis of different types of nanoparticles. The synthesis of these nanoparticles was carried out by infiltration of a suitable precursor in the pores of the silica template. The mesoporous frameworks act as molds controlling the size and the final shape of the formed nanostructures. Subsequent dissolution of the silica templates by NaOH resulted in e.g., monodispersed zirconia, hematite, and cobalt nanoparticles with narrow size distributions.

Functionalization of the SBA-15 surfaces was carried out in the synthesis of cobalt nanoparticles. This functionalization plays a crucial role on the infiltration and reaction of the reagents in the pores of the silica. By functionalization of the external surface, a highly hydrophobic surface was achieved, which proved to be sufficient to avoid formation of large cobalt particles outside the silica channels, while the internal functionalization enhances the attraction of cobalt ions to the silica pores, and as a result the nanoparticles grew inside these pores.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press , 2011. , 76 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1372
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:liu:diva-67920ISBN: 978-91-7393-156-4 (print)OAI: oai:DiVA.org:liu-67920DiVA: diva2:414233
Public defence
2011-05-31, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2013-10-02Bibliographically approved
List of papers
1. Influence of synthesis temperature on morphology of SBA-16 mesoporous materials with a three-dimensional pore system
Open this publication in new window or tab >>Influence of synthesis temperature on morphology of SBA-16 mesoporous materials with a three-dimensional pore system
2010 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 129, 106-111 p.Article in journal (Refereed) Published
Abstract [en]

Spherical particles of mesoporous silica SBA-16 with cubic Im3m structure were synthesized at low pH using Pluronic F127 as template and TEOS as silica source. The diameter of the spherical particles can be controlled in the range of 0.5–8 μm by varying synthesis temperature from 1 °C up to 40 °C. A sharp transition from large particle sizes at approximately 20 °C to smaller ones is observed when the temperature is increased. It is suggested that this morphology transition is due to a change in hydrolysis and condensation rate of the silica source and as a result the assembly of F127 micelles will differ. The SBA-16 samples were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption techniques.

Keyword
SBA-16; Spherical particles; Synthesis temperature; Morphology; F127
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:liu:diva-52757 (URN)10.1016/j.micromeso.2009.09.004 (DOI)000273862900014 ()
Note
Original Publication: Mohamed A. Ballem, José M. Córdoba and Magnus Odén, Influence of synthesis temperature on morphology of SBA-16 mesoporous materials with a three-dimensional pore system, 2010, Microporous and Mesoporous Materials, (129), 106-111. http://dx.doi.org/10.1016/j.micromeso.2009.09.004 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2010-02-02 Created: 2010-01-12 Last updated: 2017-12-12Bibliographically approved
2. Synthesis of hollow silica spheres SBA-16 with large-pore diameter
Open this publication in new window or tab >>Synthesis of hollow silica spheres SBA-16 with large-pore diameter
2011 (English)In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 65, no 7, 1066-1068 p.Article in journal (Refereed) Published
Abstract [en]

Hollow silica SBA-16 spheres with cubic ordered mesoporous shells were synthesized by an emulsion-templating method, using Pluronic F127 as a structure-directing agent. tetraethyl orthosilicateas as a silica source and heptane as a cosolvent in the presence of NH4F. The size of these spheres is in the range of 10 to 30 mu m. The shell is about 700 nm thick and consists of large pores, similar to 9 nm in diameter, arranged in a cubic order. After calcination, the spheres maintain their mesoporosity and show a high surface area of 822 m(2)/g. The formation mechanism of the silica hollow spheres is discussed.

Place, publisher, year, edition, pages
Elsevier Science B.V., Amsterdam., 2011
Keyword
Mesoporous silica, SBA-16, Hollow spheres, Large pore, F127
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-67554 (URN)10.1016/j.matlet.2011.01.035 (DOI)000289021700002 ()
Available from: 2011-04-18 Created: 2011-04-18 Last updated: 2017-12-11Bibliographically approved
3. Rapid Synthesis of SBA-15 Rods with Variable Lengths, Widths, and Tunable Large Pores
Open this publication in new window or tab >>Rapid Synthesis of SBA-15 Rods with Variable Lengths, Widths, and Tunable Large Pores
2011 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 8, 4994-4999 p.Article in journal (Refereed) Published
Abstract [en]

Dispersed SBA-15 rods have been synthesized with varying lengths, widths, and pore sizes in a low-temperature synthesis in the presence of heptane and NH4F. The pore size of the material can systematically be varied between 11 and 17 nm using different hydrothermal treatment times And/or temperatures. The particle length (400-600 nm) and width (100-400 nm) were tuned by varying the HCl concentration. All the synthesized materials possess a large surface area of 400-600 m(2)/g And a pore volume of 1.05-1.30 cm(3). A, mechanism for the effect of the HCl concentration on the particle morphology is suggested. Furthermore, it is shown that the reaction time an be decreased to 1 h, with well-retained pore size and morphology. This work has resulted in SBA-15 rods with the largest pore size reported for this morphology.

Place, publisher, year, edition, pages
ACS American Chemical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-67831 (URN)10.1021/la104864d (DOI)000289321000091 ()
Available from: 2011-04-29 Created: 2011-04-29 Last updated: 2017-12-11Bibliographically approved
4. Mesoporous silica templated zirconia nanoparticles
Open this publication in new window or tab >>Mesoporous silica templated zirconia nanoparticles
2011 (English)In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 7, 2743-2748 p.Article in journal (Refereed) Published
Abstract [en]

Nanoparticles of zirconium oxide (ZrO2)were synthesized by infiltration of a zirconia precursor(ZrOCl28H2O) into a SBA-15 mesoporous silicamold using a wet-impregnation technique. X-raydiffractometry and high-resolution transmission electronmicroscopy show formation of stable ZrO2nanoparticles inside the silica pores after a thermaltreatment at 550 C. Subsequent leaching out of thesilica template by NaOH resulted in well-dispersedZrO2 nanoparticles with an average diameter of*4 nm. The formed single crystal nanoparticles arefaceted with 110 surfaces termination suggesting it tobe the preferred growth orientation. A growth modelof these nanoparticles is also suggested.

Place, publisher, year, edition, pages
SpringerLink, 2011
Keyword
Zirconia - Nanoparticles - Mesoporous silica - Wet-impregnation - Metal oxide - Synthesis - Nanomanufacturing
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-63058 (URN)10.1007/s11051-010-0160-7 (DOI)
Available from: 2010-12-09 Created: 2010-12-09 Last updated: 2017-12-11Bibliographically approved
5. Low Temperature Nanocasting of Ultrafine Hematite Nanoparticles using Mesoporous Silica Molds
Open this publication in new window or tab >>Low Temperature Nanocasting of Ultrafine Hematite Nanoparticles using Mesoporous Silica Molds
Show others...
2012 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 217, 269-273 p.Article in journal (Refereed) Published
Abstract [en]

Iron oxide (α-Fe2O3) nanoparticles with very small size, high crystallinity, and narrow size distribution were synthesized by infiltration of Fe(NO3)3.9H2O as an oxide precursor into mesoporous silica (SBA-15 and SBA-16) molds using a wetimpregnation technique. High resolution transmission electron microscopy shows that during the hydrothermal treatment of the precursor at 140 °C for 2 days, stable α-Fe2O3 nanoparticles inside the silica pores are formed. Subsequent leaching out of the silica template by NaOH resulted in well dispersed nanoparticles with an average diameter of ~ 4 nm.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
α-Fe2O3, Nanoparticles, Nanocasting, Mesoporous silica, SBA-15, SBA-16
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-67915 (URN)10.1016/j.powtec.2011.10.037 (DOI)000301159500034 ()
Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2017-12-11
6. Synthesis of homogeneously dispersed cobalt nanoparticles in the pores of functionalized SBA-15 silica
Open this publication in new window or tab >>Synthesis of homogeneously dispersed cobalt nanoparticles in the pores of functionalized SBA-15 silica
Show others...
2012 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 221, no S1, 359-364 p.Article in journal (Refereed) Published
Abstract [en]

Cobalt nanoparticles were prepared at room temperature by reducing cobalt sulfate heptahydrate with sodium borohydride and using functionalized SBA-15 mesoporous silica as a hard template. It was found that both external and internal fuctionalization of silica walls play a crucial role on the infiltration and reaction of the reagents in the silica framework. Subsequent heat treatment of the impregnated silica at 500 °C in air or nitrogen atmospheres leads to growth of crystals of the deposited cobalt and formation of cobalt and cobalt oxide nanoparticles, respectively. Dissolution of the silica template by NaOH resulted in well dispersed Co and Co3O4 nanoparticles ranging in size from 2 to 4 nm. The functionalization of the silica was studied by FTIR, N2-physisorption, and thermogravimetric techniques and the obtained nanoparticles were characterized by XRD, TEM and EDX analysis.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
Functionalization; Cobalt; Cobalt oxide; Nanoparticles; SBA-15 silica; Sodium borohydride
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-67917 (URN)10.1016/j.powtec.2012.01.025 (DOI)000303222300046 ()
Note
funding agencies|Swedish International Development Cooperation Agency, Sida||Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2017-12-11Bibliographically approved
7. Growth of Gd2O3 nanoparticles inside mesoporous silica frameworks
Open this publication in new window or tab >>Growth of Gd2O3 nanoparticles inside mesoporous silica frameworks
Show others...
2013 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 168, 221-224 p.Article in journal (Refereed) Published
Abstract [en]

Gadolinium oxide (Gd2O3) nanoparticles with very small size, and narrow size distribution were synthesized by infiltration of Gd(NO3)3.6H2O as an oxide precursor into the pores of SBA-15 mesoporous silica using a wet-impregnation technique. High resolution transmission electron microscopy and X-ray diffraction show that during the hydrothermal treatment of the precursor at 550 °C, gadolinium oxide nanoparticles inside the silica pores are formed. Subsequent dissolution of the silica template by NaOH resulted in well dispersed nanoparticles with an average diameter of 3.6 ± 0.9 nm.

Place, publisher, year, edition, pages
Elsevier, 2013
Keyword
Gd2O3; Nanoparticles; Nanocasting; Mesoporous silica; SBA-15
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-67918 (URN)10.1016/j.micromeso.2012.10.009 (DOI)000313839800030 ()
Note

At the time of the defence, this publication was an unsubmitted manuscript

Available from: 2011-05-02 Created: 2011-05-02 Last updated: 2017-12-11Bibliographically approved

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  • en-US
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  • nn-NB
  • sv-SE
  • Other locale
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Output format
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