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Chang, Juyeon and Jung, Duk-Young*

Synthesis and Characterization of Mesostructured Vanadium Oxide. Department of Chemistry-BK21, SungKyunKwan University, Suwon 440-746, Korea. Chang, Juyeon and Jung, Duk-Young*. Contents. SKKU Inorganic Materials Lab. Introduction : Mesoporous Materials.

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Chang, Juyeon and Jung, Duk-Young*

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  1. Synthesis and Characterization of Mesostructured Vanadium Oxide Department of Chemistry-BK21, SungKyunKwan University, Suwon 440-746, Korea Chang, Juyeon and Jung, Duk-Young*

  2. Contents SKKU Inorganic Materials Lab. • Introduction • : Mesoporous Materials 2. Synthesis of Vanadate/Surfactant Clusters. 3. Hydrothermal reaction of Vanadate/Surfactant Clusters. : 1) As temperature is varied 2) As pH is varied • Effect on UV/O3 Treatment • :As time is varied 5. Conclusion

  3. Introduction Microporous Mesoporous Macroporous hexagonal array surfactant micelle micellar rod 5 10 50 100 500 1000 Pore size / Å J. S.Beck et al., J. Am. Chem. Soc.1992, 114, 10834. SKKU Inorganic Materials Lab. Based on Surfactant-Assisted Ordering silicate calcination MCM-41 C. T. Kresge et al., Nature, 1992, 359, 710.

  4. Vanadate Solution Speciation SKKU Inorganic Materials Lab. Solution 51V NMR spectra of vanadate solutions with various pH. Predominance diagram for V(V)-OH- species 1 3 5 V. Luca et al., Chem. Mater.1992, 9, 2731.

  5. Procedure I SKKU Inorganic Materials Lab. 1. VOxn- (pH, conc. control) : 0.15M NaVO3 solution(pH8.2(1), 6.7(3) and 5.0(5)) with addition of 2M HCl soln. 2. VOxn- + C16TMA-Bromide : Addition of excess CH3(CH2)15N(CH3)3Br soln.(wt 2.7%) to vanadate soln 3. The colored precipitates are obtained. : C16TMA-V1(white, pH8.4), C16TAM-V3(pale- yellow, pH6.5) and C16TMA-V5(orange, pH4.8) filtered, washing with double distilled water. - C16TMA-Bromide (cetyltrimethylammonium bromide ) -

  6. Structure of Vanadate-C16TMA Clusters SKKU Inorganic Materials Lab. Powder XRD Patterns FT-IR spectra V-O-V banding (tetrahedral) VO3 stretching V-O-V banding(octaherdal)

  7. Kanemite Transformation SKKU Inorganic Materials Lab. A. Monnier et al., Science.1993, 261, 1299. Hydrothermal Reaction

  8. Procedure II SKKU Inorganic Materials Lab. • Hydrothermal Reaction at Various Temperatures. • : Starting material : C16TMA-V1, C16TA-V3 and C16TMA-V5. • Solvent : double distilled water. • Temperature : 403K, 433K, and 463K • Hydrothermal Reaction after pH control. • : Starting material : C16TMA-V1, C16TA-V3 and C16TMA-V5. • Solvent : double distilled water. • Temperature : 433K

  9. At Various Temperatures I SKKU Inorganic Materials Lab. Powder XRD Patterns for C16TMA-V1 Powder XRD Patterns for C16TMA-V5 L : lamellar, H : hexagonal structure

  10. At Various Temperatures II SKKU Inorganic Materials Lab. Powder XRD Patterns for C16TMA-V3 Index d(Å) 100 51.4 110 29.6 200 26.7 300 17.4

  11. Calcination SKKU Inorganic Materials Lab. Thermogravimetric analysis for hexagonal structure Powder XRD Patterns for hexagonal structure

  12. After pH control I SKKU Inorganic Materials Lab. Powder XRD Patterns for C16TMA-V1 Powder XRD Patterns for C16TMA-V3

  13. After pH control II SKKU Inorganic Materials Lab. Powder XRD Patterns for C16TMA-V5 Index d(Å) 111 44.6 200 38.6 211 31.6 220 27.4 221 25.8 311 23.4 222 22.2 C : cubic structure

  14. After pH control III SKKU Inorganic Materials Lab. 50 nm Powder XRD Patterns for C16TMA-V3 TEM image for the sample at 463K The C16TMA-V3 in ethanol and the pH 2.2 with HCl Resulting brown product was filtered. Hydrothermal reaction at 463K.

  15. Effect on UV/O3 Application SKKU Inorganic Materials Lab. Powder XRD Patterns for UV/O3 treated sample FT-IR spectra for UV/O3 treated sample Using UV/O3 lamp (electrical power 20W, UV power 5W at 254 and 180nm).

  16. Conclusion SKKU Inorganic Materials Lab. I The resulting composites had lamellar structures and displayed mesophase transformation to hexagonal and cubic structures after hydrothermal treatment of vanadate-surfactant composite powders. However, they are thermally unstable. UV/ozone treatment provides an efficient means for the condensation of vanadate clusters, but not efficient for removing of organic surfactant. II It is speculated that the results are due to the poor condensation of vandates or the strong interaction between the inorganic framework and the organic template.

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