liu.seSearch for publications in DiVA
Change search
Refine search result
1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ballem, Mohamed A.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Synthesis of Mesoporous Silica and their Use as Templates for Metal and Metal Oxide Nanoparticles2011Doctoral 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.

    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, p. 106-111Article 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.

    Keywords
    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, p. 1066-1068Article 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
    Keywords
    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, p. 4994-4999Article 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, p. 2743-2748Article 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
    Keywords
    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, p. 269-273Article 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
    Keywords
    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, p. 359-364Article 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
    Keywords
    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, p. 221-224Article 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
    Keywords
    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
  • 2.
    Ballem, Mohamed A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Córdoba, José M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Influence of synthesis temperature on morphology of SBA-16 mesoporous materials with a three-dimensional pore system2010In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 129, p. 106-111Article in journal (Refereed)
    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.

  • 3.
    Ballem, Mohamed A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Córdoba, José
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Mesoporous silica templated zirconia nanoparticles2011In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 7, p. 2743-2748Article in journal (Refereed)
    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.

  • 4.
    Ballem, Mohamed A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Zhang, Xuanjun
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Johansson, Emma M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Córdoba, José M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Low Temperature Nanocasting of Ultrafine Hematite Nanoparticles using Mesoporous Silica Molds2012In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 217, p. 269-273Article in journal (Refereed)
    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.

  • 5.
    Ballem, Mohamed Ali
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Nordblad, Per
    Uppsala Unversity, Sweden.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Growth of Gd2O3 nanoparticles inside mesoporous silica frameworks2013In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 168, p. 221-224Article in journal (Refereed)
    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.

  • 6.
    Ballem, Mohamed
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Johansson, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Cordoba Gallego, Jose Manuel
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Synthesis of hollow silica spheres SBA-16 with large-pore diameter2011In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 65, no 7, p. 1066-1068Article in journal (Refereed)
    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.

  • 7.
    Cordoba Gallego, Jose Manuel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Ballem, Mohamed
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Johansson, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Growth of single crystalline dendritic Li(2)SiO(3) arrays from LiNO(3) and mesoporous SiO(2)2011In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 184, no 7, p. 1735-1739Article in journal (Refereed)
    Abstract [en]

    A solution based wet chemistry approach has been developed for synthesizing Li(2)SiO(3) using LiNO(3) and mesoporous silica as starting materials at 550 degrees C. A reaction path where NO and O(2) are formed as side-products is proposed. The crystals synthesized exhibit dendritic growth where the as-prepared nanodendrite is a typical 1-fold nanodendrite composed of one several microns long and some tenth of nanometers wide trunk with small branches, which are several hundreds of nanometers long and up to 70 nm in diameter. The effect of the structure of the mesoporous silica for the final morphology is discussed.

  • 8.
    Escalera, Edwin
    et al.
    Division of Engineering Materials, Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, Luleå, Sweden..
    Ballem, Mohamed A.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Cordoba, José M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Antti, Marta-Lena
    Division of Engineering Materials, Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, Luleå, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Synthesis of homogeneously dispersed cobalt nanoparticles in the pores of functionalized SBA-15 silica2012In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 221, no S1, p. 359-364Article in journal (Refereed)
    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.

  • 9.
    Johansson, Emma
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Ballem, Mohamed
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Cordoba Gallego, Jose Manuel
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Rapid Synthesis of SBA-15 Rods with Variable Lengths, Widths, and Tunable Large Pores2011In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 8, p. 4994-4999Article in journal (Refereed)
    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.

  • 10.
    Tsai, H T
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Cordoba Gallego, Jose Manuel
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Johansson, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Ballem, Mohamed
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Silica SBA-15 Template Assisted Synthesis of Ultrasmall and Homogeneously Sized Copper Nanoparticles2011In: JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, ISSN 1533-4880, Vol. 11, no 4, p. 3493-3498Article in journal (Refereed)
    Abstract [en]

    The synthesis of spherical copper nanoparticles with extremely narrow size distribution by electroless copper deposition on mesoporous silica support is described. The materials were characterized by nitrogen sorption, transmission electron microscopy, x-ray diffractometry and Fourier transform infrared spectroscopy. The copper nanoparticles have a cubic crystalline structure and an average particle size of 5.5 +/- 0.8 nm. The copper nanoparticles are stable, without detectable oxidation or further agglomeration under ambient conditions even after months. These results demonstrate that electroless copper reduction can be conducted and constrained within the mesoporous silica framework, which pave the way for engineered mesoreactors.

  • 11.
    Zhang, Xuanjun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Ali Ballem, Mohamed
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Nanoscale Ln(III)-carboxylate coordination polymers (Ln = Gd, Eu, Yb): temperature-controlled guest encapsulation and light harvesting2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 30, p. 10391-10397Article in journal (Refereed)
    Abstract [en]

    We report the self-assembly of stable nanoscale coordination polymers (NCPs), which exhibit temperature-controlled guest encapsulation and release, as well as an efficient light-harvesting property. NCPs are obtained by coordination-directed organization of pi-conjugated dicarboxylate (L1) and lanthanide metal ions Gd(III), Eu(III), and Yb(III) in a DMF system. Guest molecules trans-4-styryl-1-methylpyridiniumiodide (D1) and methylene blue (D2) can be encapsulated into NCPs, and the loading amounts can be controlled by changing reaction temperatures. Small angle X-ray diffraction (SAXRD) results reveal that the self-assembled discus-like NCPs exhibit long-range ordered structures, which remain unchanged after guest encapsulations. Experimental results reveal that the negatively charged local environment around the metal connector is the driving force for the encapsulation of cationic guests. The D1 molecules encapsulated in NCPs at 140 degrees C can be released gradually at room temperature in DMF. Guest-loaded NCPs exhibit efficient light harvesting with energy transfer from the framework to the guest D1 molecule, which is studied by photoluminescence and fluorescence lifetime decays. This coordination-directed encapsulation approach is general and should be extended to the fabrication of a wide range of multifunctional nanomaterials.

  • 12.
    Zhang, Xuanjun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Ballem, Mohamed
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hu, Zhang-Jun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bergman, J Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Nanoscale Light-Harvesting Metal-Organic Frameworks2011In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 50, no 25, p. 5728-5732Article in journal (Refereed)
    Abstract [en]

    n/a

1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf