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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

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SKKU Inorganic Materials Lab. Contents 1.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 4.Effect on UV/O 3 Treatment :As time is varied 5. Conclusion

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SKKU Inorganic Materials Lab. Introduction Microporous Mesoporous Macroporous Pore size / 510501005001000 J. S. Beck et al., J. Am. Chem. Soc. 1992, 114, 10834. Based on Surfactant-Assisted Ordering C. T. Kresge et al., Nature, 1992, 359, 710. surfactant micelle micellar rod hexagonal array silicate calcination MCM-41

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

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SKKU Inorganic Materials Lab. Procedure I 1. VO x n- (pH, conc. control) : 0.15M NaVO 3 solution(pH8.2(1), 6.7(3) and 5.0(5)) with addition of 2M HCl soln. 2. VO x n- + C 16 TMA-Bromide : Addition of excess CH 3 (CH 2 ) 15 N(CH 3 ) 3 Br soln.(wt 2.7%) to vanadate soln 3. The colored precipitates are obtained. : C 16 TMA-V1(white, pH8.4), C 16 TAM-V3(pale- yellow, pH6.5) and C 16 TMA-V5(orange, pH4.8) filtered, washing with double distilled water. - C 16 TMA-Bromide (cetyltrimethylammonium bromide ) -

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SKKU Inorganic Materials Lab. Structure of Vanadate-C 16 TMA Clusters VO 3 stretching V-O-V banding (tetrahedral) V-O-V banding(octaherdal) Powder XRD Patterns FT-IR spectra

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

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SKKU Inorganic Materials Lab. Procedure II 1.Hydrothermal Reaction at Various Temperatures. : Starting material : C 16 TMA-V1, C 16 TA-V3 and C 16 TMA-V5. Solvent : double distilled water. Temperature : 403K, 433K, and 463K 2.Hydrothermal Reaction after pH control. : Starting material : C 16 TMA-V1, C 16 TA-V3 and C 16 TMA-V5. Solvent : double distilled water. Temperature : 433K

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SKKU Inorganic Materials Lab. At Various Temperatures I Powder XRD Patterns for C 16 TMA- V1 Powder XRD Patterns for C 16 TMA- V5 L : lamellar, H : hexagonal structure

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SKKU Inorganic Materials Lab. At Various Temperatures II Powder XRD Patterns for C 16 TMA-V3 Index d() 100 51.4 110 29.6 200 26.7 300 17.4

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

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SKKU Inorganic Materials Lab. After pH control I Powder XRD Patterns for C 16 TMA- V1 Powder XRD Patterns for C 16 TMA-V3

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SKKU Inorganic Materials Lab. After pH control II Powder XRD Patterns for C 16 TMA-V5 Index d() 111 44.6 200 38.6 211 31.6 220 27.4 221 25.8 311 23.4 222 22.2 C : cubic structure

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SKKU Inorganic Materials Lab. After pH control III 50 nm Powder XRD Patterns for C 16 TMA-V3 TEM image for the sample at 463K The C 16 TMA-V3 in ethanol and the pH 2.2 with HCl Resulting brown product was filtered. Hydrothermal reaction at 463K.

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SKKU Inorganic Materials Lab. Effect on UV/O 3 Application Using UV/O 3 lamp (electrical power 20W, UV power 5W at 254 and 180nm). Powder XRD Patterns for UV/O 3 treated sample FT-IR spectra for UV/O 3 treated sample

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SKKU Inorganic Materials Lab. Conclusion 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.