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Resasco D.E. Alvarez W.E. Pompeo F. Balzano L. Herrera J.E. Kitiyanan B. Borgna A. 《Journal of nanoparticle research》2002,4(1-2):131-136
Existing single-walled carbon nanotube synthesis methods are not easily scalable, operate under severe conditions, and involve high capital and operating costs. The current cost of SWNT is exceedingly high. A catalytic method of synthesis has been developed that has shown potential advantages over the existing methods. This method is based on a catalyst formulation that inhibits the formation of undesired forms of carbon; it can be scaled-up and may result in lower production costs. 相似文献
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Yindee Suttisawat Pramoch Rangsunvigit Boonyarach Kitiyanan Santi Kulprathipanja 《Journal of Solid State Electrochemistry》2010,14(10):1813-1819
Sodium aluminum hydride or sodium alanate (NaAlH4) has been considered as a potential material for hydrogen storage. Although its theoretical hydrogen storage capacity is
5.5 wt.% at 250 °C, the material still has its drawback in the regeneration issue. With the use of certain catalysts, the
regeneration problem can somewhat be alleviated with added benefits in the decrease in the hydrogen decomposition temperature
and the increase in the decomposition rate. This work summarizes what we have learned from the decomposition of NaAlH4 with/without catalysts and co-dopants. The decomposition was carried out using a thermovolumetric apparatus. For the tested
catalysts—HfCl4, VCl3, TiO2, TiCl3, and Ti—the decomposition temperature of the hydride decreases; however, they affect the temperature in the subsequent cycles
differently and TiO2 appears to have the most positive effect on the temperature. Sample segregation and the morphological change are postulated
to hinder the reversibility of the hydride. To prevent the problems, co-dopants—activated carbon, graphite, and MCM-41—were
loaded. Results show that the hydrogen reabsorption capacity of HfCl4- and TiO2-doped NaAlH4 added with the co-dopants increases 10–50% compared with that without a co-dopant, and graphite is the best co-dopant in
terms of reabsorption capacity. In addition, the decomposition temperature in the subsequent cycles of the co-dopant doped
samples decreases about 10–15 °C as compared to the sample without a co-dopant. Porosity and large surface area of the co-dopant
may decrease the segregation of bulk aluminum after the desorption and improve hydrogen diffusion in/out bulk of desorbed/reabsorbed
samples. 相似文献
3.
The preparation and characterization of nanostructured TiO2-ZrO2 mixed oxide electrode for efficient dye-sensitized solar cells 总被引:1,自引:0,他引:1
Athapol Kitiyanan 《Journal of solid state chemistry》2005,178(4):1044-1048
The preparation of nanostructured mixed metal oxide based on a sol-gel method with surfactant-assisted mechanism, and its application for dye-sensitized solar cell (DSSC) are reported. The mixed zirconia (ZrO2) and titania (TiO2) mesoporous powder possessed larger surface area than the corresponding titania. For the UV action spectra of unsensitized photochemical cell, the mixed zirconia/titania electrode can absorb UV light below 380 nm, corresponding to band gap (Eg) around 3.27 eV, which is higher than that of pure component of titania (). Both of these improved properties, i.e., BET surface area and band gap, contributed to the improvement on a short-circuit photocurrent up to 11%, an open-circuit voltage up to 4%, and a solar energy conversion efficiency up to 17%, for the DSSC fabricated by mesoporous zirconia/titania mixed system when compared to the cell that was fabricated only by nanostructured TiO2. The cell fabricated by 5 μm thick mixed TiO2-ZrO2 electrode gave the short-circuit photocurrent about 13 mA/cm2, open-circuit voltage about 600 mV and the conversion efficiency 5.4%. 相似文献
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Wannida Apisuk Naohiro Suzuki Hyun Joon Kim Dong Hyun Kim Boonyarach Kitiyanan Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2565-2574
Aryloxo‐modified half‐titanocenes, Cp′TiCl2(O‐2,6‐iPr2C6H3) [Cp′ = Cp* ( 1 ), tBuC5H4 ( 2 )], catalyze terpolymerization of ethylene and styrene with α‐olefin (1‐hexene and 1‐decene) efficiently in the presence of cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions (compositions). Efficient comonomer incorporations have been achieved by these catalysts. The content of each comonomer (α‐olefin, styrene, etc.) could be controlled by varying the comonomer concentration charged, and resonances ascribed to styrene and α‐olefin repeated insertion were negligible. The terpolymerization with p‐methylstyrene (p‐MS) in place of styrene also proceeded in the presence of [PhN(H)Me2][B(C6F5)4] and AliBu3 cocatalyst, and p‐MS was incorporated in an efficient matter, affording high‐molecular‐weight polymers with uniform molecular weight distributions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2565–2574 相似文献
5.
Wannida Apisuk Boonyarach Kitiyanan Hyun Joon Kim Dong Hyun Kim Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2581-2587
An efficient introduction of vinyl group into poly (ethylene‐co‐styrene) or poly(ethylene‐co?1‐hexene) has been achieved by the incorporation of 3,3′‐divinylbiphenyl (DVBP) in terpolymerization of ethylene, styrene, or 1‐hexene with DVBP using aryloxo‐modified half‐titanocenes, Cp′TiCl2(O?2,6‐iPr2C6H3) [Cp′ = Cp*, tBuC5H4, 1,2,4‐Me3C5H2], in the presence of MAO cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions. Efficient comonomer incorporations have been achieved by these catalysts, and the content of each comonomer could be varied by its initial concentration charged. The postpolymerization of styrene was initiated from the vinyl group remained in the side chain by treatment with n‐BuLi. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2581–2587 相似文献
6.
Takashi Fuyuki Athapol Kitiyanan 《Applied Physics A: Materials Science & Processing》2009,96(1):189-196
The photographic surveying of electroluminescence (EL) under forward bias was proved to be a powerful diagnostic tool for
investigating not only the material properties but also process induced deficiencies visually in silicon (Si) solar cells.
Under forward bias condition, solar cells emit infrared light (wavelength around 1000 to 1200 nm) whose intensity reflects
the number of minority carriers in base layers. Thus, all the causes that affect the carrier density can be detected, i.e.,
the minority carrier diffusion length (or in other words, lifetime), recombination velocity at surfaces and interfaces, etc.
(intrinsic material properties), and wafer breakage and electrode breakdown, etc. (extrinsic defects). The EL intensity distribution
can be captured by Si CCD camera in less than 1 s, and the detection area simply depends upon the optical lens system suitable
to the wide range of 1 cm–1.5 m. This fast and precise technique is superior to the conventional scanning method such as the
laser beam induced current (LBIC) method.
The EL images are displayed as grayscale, which leads to the difficulty of distinguishing the sorts of those deficient areas.
Since the intrinsic deficiency is more sensitive to temperature than the extrinsic deficiency, the change in solar cell temperature
can offer the difference in EL intensity contrasts. These effects upon the measurement temperature can be applied to categorize
the types of deficiency in the crystalline Si solar cell. 相似文献
7.
Wannida Apisuk Alexandra G. Trambitas Boonyarach Kitiyanan Matthias Tamm Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2575-2580
Ethylene copolymerizations with norbornene (NBE) using half‐titanocenes containing imidazolin‐2‐iminato ligands, Cp′TiCl2[1,3‐R2(CHN)2C?N] [Cp′ = Cp ( 1 ), tBuC5H4 ( 2 ); R = tBu ( a ), 2,6‐iPr2C6H3 ( b )], have been explored in the presence of methylaluminoxane (MAO) cocatalyst. Complex 1a exhibited remarkable catalytic activity with better NBE incorporation, affording high‐molecular‐weight copolymers with uniform molecular weight distributions, whereas the tert‐BuC5H4 analog ( 2a ) showed low activity, and the resultant polymer prepared by the Cp‐2,6‐diisopropylphenyl analog ( 1b ) possessed broad molecular weight distribution. The microstructure analysis of the poly(ethylene‐co‐NBE)s prepared by 1a suggests the formation of random copolymers including two and three NBE repeating units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2575–2580 相似文献
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