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Thuy-Duong Nguyen-Phan Myoung Bok Song Eui Jung Kim Eun Woo Shin 《Research on Chemical Intermediates》2010,36(6-7):613-619
One-dimensional titania nanomaterials were synthesized by soft chemical processes in an alkali medium. The effect of alkali-treatment temperature on the morphology, porosity, and crystalline phase of TiO2 nanomaterials was investigated. Nanotubes having an opening end were observed when aging the sample at 130 °C, while conducting the process at 180 °C resulted in nanoribbons with a high aspect ratio. Post-treatment at 300 °C led to the partial transformation from tubular structures into nanoparticles or ribbons into nanobelts. While the monoclinic sodium hexatitanate and anatase crystal had a tubular structure, nanoribbons and nanobelt TiO2 also showed the presence of hydrogen titanate and sodium trititanate. High surface areas were achieved in as-prepared nanotubes and nanoribbons, 456.5 and 72.1 m2/g, respectively, and a drastic reduction was obtained upon post-treatment at 300 °C to 72.1 and 19.2 m2/g, respectively. 相似文献
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Synthesis of the chemically converted graphene xerogel with superior electrical conductivity 总被引:1,自引:0,他引:1
Pham HD Pham VH Cuong TV Nguyen-Phan TD Chung JS Shin EW Kim S 《Chemical communications (Cambridge, England)》2011,47(34):9672-9674
The ultra-low density graphene xerogel was prepared through the chemical reduction of graphene oxide suspension using a hypophosphorous acid-iodine mixture. The chemically converted graphene xerogel (CCGX) exhibited superior electrical conductivity (up to 500 S m(-1)) and high C/O atomic ratio (14.7), which were the highest values reported for the graphene-based xerogel. 相似文献
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Thuy-Duong Nguyen-Phan Chae Young Lee Jin Suk Chung Eun Woo Shin 《Research on Chemical Intermediates》2008,34(8-9):743-753
Mesoporous molecular sieve SBA-15 modified by titanium has been utilized for removing organic pollutants, such as benzene, from air. Titanium was impregnated inside SBA-15 by wetness impregnation after synthesis of SBA-15 (impregnation method) or was doped into the SBA-15 framework by the direct addition of Ti precursor into the sol during synthesis (doping method). In the breakthrough curves for gas-phase benzene adsorption, Ti addition into SBA-15 resulted in the enhancement of benzene adsorption capacity, depending on Ti loading amounts. An increase in adsorption temperature remarkably reduced the benzene adsorption capacity, indicating that the interaction between benzene and the materials was weak. 相似文献
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Ngo NT Nguyen VT Vo HV Vang O Duus F Ho TD Pham HD Nguyen LH 《Chemical & pharmaceutical bulletin》2010,58(11):1487-1491
A new geranylated coumarin, (E)-4-(1-hydroxypropyl)-5,7-dihydroxy-6-(3,7-dimethyl-2,6-octadienyl)-8-(3-methyl-1-oxobutyl)coumarin (named surangin D), was isolated from the bark of Mammea siamensis collected in Vietnam, along with four known coumarins, surangins B and C, and theraphins B and C, and seven xanthones, 1,7-dihydroxyxanthone, 7-hydroxy-1-methoxyxanthone, 1,7-dimethoxyxanthone, 1,7-dimethoxy-6-hydroxyxanthone, 1,6,7-trihydroxyxanthone, 1,3,7-trihydroxyxanthone, and 1,7-dihydroxy-3-methoxyxanthone. Their structures were determined by spectroscopic methods (mainly 1D- and 2D-NMR) and preparation of methylated derivatives. The four coumarins, surangins C and D and theraphins B and C, were tested for inhibition of cell proliferation in DLD-1 (colon cancer), MCF-7 (breast adenocarcinoma), HeLa (human cervical cancer) and NCI-H460 (human lung cancer) cell lines using the sulforhodamine B (SRB) assay. In all four cell lines, theraphin C showed the strongest activity (IC?? in the range of 1.6-5.7 μM). Testing the anti-proliferative effect of the methylated derivatives showed reduced cellular effects of all derivatives, indicating that the number and position of free hydroxyl groups were very important for the anti-proliferative effect. 相似文献
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Thuy-Duong Nguyen-PhanMyoung Bock Song Hyunran YunEui Jung Kim Eun-Suok OhEun Woo Shin 《Applied Surface Science》2011,257(6):2024-2031
A series of vanadium-doped mesoporous titania with different metal contents was synthesized in the study via a sol-gel process with the assistance of a dodecylamine surfactant. The existence of vanadium ions not only suppressed crystallization and sintering but also enhanced the porosity of the mesoporous TiO2. Varying the vanadium concentration led to significant changes in the chemical oxidation state of each component. The presence of metal dopants significantly improved the removal efficiency of benzene and the doping the titania with 5 mol% vanadium removed the most benzene, regardless of the adsorption temperature. The adsorption behavior was elucidated by the specific surface area, the interactions between surface hydroxyl groups and the π-electrons of benzene, and the formation of σ-bonding and d-π* back-donation between the adsorbent and organic compounds. 相似文献
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Nguyen-Phan TD Kim EJ Hahn SH Kim WJ Shin EW 《Journal of colloid and interface science》2011,356(1):138-144
Novel hierarchical rose bridal bouquet- and humming-top-like nanostructured TiO(2) were successfully prepared by the simple process with the hydrothermal temperature as the morphology-controlling factor. The gradual transformation from layered titanate to brookite phase was well consistent with the formation mechanism of the hierarchical morphologies. The three-dimensional flower bouquets built from the bunches of roses with surrounding fern fronds displayed the best adsorptivity and completely degraded methylene blue within 60 min under UV irradiation, whereas the humming-top geometry composed of anisotropically elongated spindle-like crystallites was detrimental to the dye photodegradation. 相似文献
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Nguyen-Phan TD Pham VH Kweon H Chung JS Kim EJ Hur SH Shin EW 《Journal of colloid and interface science》2012,367(1):139-147
Reduced graphene oxide-TiO(2) hybrids were successfully prepared by the hydrothermal approach using triethanolamine and acetylacetone as the chelating agents. Without any additive, large aggregated TiO(2) clusters were randomly distributed dominantly at the edge and less on the basil plane of coagulated reduced graphene oxide (RGO) layers. The presence of chelating ligands remarkably facilitated the selective growth and regular spread of TiO(2) nanocrystals onto individually exfoliated RGO sheet. Such sandwich-like structure with stronger coupling and chemical interaction resulted in the surface area increase, the rearrangement of energy level, the enhanced concentration of oxygen vacancies, leading to much higher adsorbability and photocatalytic degradation of Rhodamine B under both UV and visible irradiations. These RGO-TiO(2) hybrid systems are potentially beneficial for widely practical applications in air/water purification, electronic devices, batteries, solar cells or supercapacitors. 相似文献
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