• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.469-472
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• 2012

Intensity modulated photocurrent spectroscopy and intensity modulated photovoltage spectroscopy were investigated to measure the dynamic response of charge transfer and recombination in the standard, $TiCl_4$-treated and the combined scattering layer electrode dye-sensitized solar cells (DSSCs). IMPS and IMVS provided transit time ($\tau_n$), lifetime ($\tau_r$), diffusion coefficient ($D_n$) and effective diffusion length ($L_n$). These expressions are derived that generation, collection, and recombination of electrons in a thin layer nanocrystalline DSSC under conditions of steady illumination and with a superimposed small amplitude modulation. In this experimental, IMPS/IMVS showed that the main effect of $TiCl_4$ treatment is to suppress the recombination of photogenerated electrons, thereby extending their lifetime. And the Diffusion coefficient of combined scattering layer electrode is $6.10{\times}10^{-6}$ higher than that of the others, resulting in longer diffusion length.

• Journal of Electrochemical Science and Technology
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• v.1 no.2
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• pp.81-84
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• 2010

In dye-sensitized solar cells (DSSCs), the back transfer of photo-generated electrons from FTO glass to triiodide ions in an electrolyte is an important loss mechanism, which leads to low cell efficiency. Recently, this back electron transfer was greatly suppressed by the introduction of a compact $TiO_2$ blocking layer, which was prepared by the treatment of $TiCl_4$ solution. In the present work, more detailed $TiCl_4$ treated surface conditions on FTO substrate were investigated and DSSC performances were correlated with the surface morphology as well as dark current behavior.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.689-691
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• 1993

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.681-686
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• 2004

Ti-ZSM-5 prepared by secondary synthesis, from the reaction of H-ZSM-5 with vapor phase $TiCl_4$, was characterized with several physicochemical techniques including FT-IR and UV/VIS-DRS. It was found that zeolite structure, surface area and pore volume did not change, and the framework aluminum could not be replaced by titanium atom during the secondary synthesis of Ti-ZSM-5. The incorporation of titanium into the framework might be due to reaction of $TiCl_4$with the silanol groups associated with defects or surface sites. The formation of extra-framework titanium could not be avoided, unless the samples were further treated by water vapor at 550 $^{\circ}C$ or higher temperature. High temperature steam treatment of Ti-ZSM-5 prepared by chemical vapor deposition with $TiCl_4$was efficient to prevent the formation of non-framework titanium species. Ti-ZSM-5 zeolites prepared in this work contained only framework titanium species and exhibited improved catalytic property close to TS-1 prepared by hydrothermal synthesis.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.254-260
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• 2024

This study is to manufacture a titanium dioxide (TiO₂) photocatalyst by recycling sludge generated using titanium tetrachloride (TiCl₄) as a coagulant. Compared to general sewage, a TiCl₄ coagulant was applied to dyeing wastewater containing a large amount of non-degradable organic compounds to evaluate its performance. Then the generated sludge was dried and fired to prepare a photocatalyst (TFS). Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and nitrogen oxide reduction experiments were conducted to analyze the surface properties and evaluate the photoactive ability of the prepared TFS. After using titanium tetrachloride (TiCl₄) as a coagulant in the dyeing wastewater, the water quality characteristics were measured at 84 mg/L of chemical oxygen demand (COD), 10 mg/L of T-N, and 0.9 mg/L of T-P to satisfy the discharge water quality standards. The surface properties of the TFS were investigated and the anatase crystal structure was observed. It was confirmed that the ratio of Ti and O, the main components of TiO₂, accounted for more than 90 %. As a result of the nitric oxide (NO) reduction experiment, 1.56 uMol of NO was reduced to confirm a removal rate of 20.60 %. This is judged to be a photocatalytic performance similar to that of the existing P-25. Therefore, by applying TiCl₄ to the dyeing wastewater, it is possible to solve the problems of the existing coagulant and to reduce the amount of carbon dioxide generated, using an eco-friendly sludge treatment method. In addition, it is believed that environmental and economic advantages can be obtained by manufacturing TiO₂ at an eco-friendly and lower cost than before.

• Bulletin of the Korean Chemical Society
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• v.20 no.8
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• pp.893-896
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• 1999

Novel citric acid based Ti, Nb and Ta precursors that are highly stable in the presence of water were developed. No alkoxides of Ti, Nb and Ta were utilized in the preparation, instead much less moisture-sensitive metallic Ti, NbCl5 and TaCl5 were chosen as starting chemicals for Ti, Nb and Ta, respectively. The feasibility of these chemicals as precursors is demonstrated in the powder synthesis of BaTi4O9, Y3NbO7 and LiTaO3. The water-resistant Ti precursor was employed as a new source of water-soluble Ti in the amorphous citrate method, and phase pure BaTi4O9 in powdered form was successfully synthesized at 800 ？. The Pechini-type polymerizable complex method using the water-resistant Nb and Ta precursors was applied to the synthesis of Y3NbO7 and LiTaO3, and both the powder materials in their pure form were successfully synthesized at reduced tempera-tures, viz. 500-700 ？. The remarkable retardation of hydrolysis of these water-resistant precursors is explained in terms of the partial charge model theory.

• Korean Journal of Materials Research
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• v.20 no.12
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• pp.669-675
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• 2010

One of the greatest challenges for our society is providing powerful electrochemical energy conversion and storage devices. Rechargeable lithium-ion batteries and fuel cells are among the most promising candidates in terms of energy and power density. As the starting material, $TiCl_4{\cdot}YCl_3$ solution and dispersing agent (HCP) were mixed and synthesized using ammonia as the precipitation agent, in order to prepare the nano size Y doped spherical $TiO_2$ precursor. Then, the $Li_4Ti_5O_{12}$ was synthesized using solid state reaction method through the stoichiometric mixture of Y doped spherical $TiO_2$ precursor and LiOH. The Ti mole increased the concentration of the spherical particle size due to the addition of HPC with a similar particle size distribution in a well in which $Li_4Ti_5O_{12}$ spherical particles could be obtained. The optimal synthesis conditions and the molar ratio of the Ti 0.05 mol reaction at $50^{\circ}C$ for 30 minutes and at $850^{\circ}C$ for 6 hours heat treatment time were optimized. $Li_4Ti_5O_{12}$ was prepared by the above conditions as a working electrode after generating the Coin cell; then, electrochemical properties were evaluated when the voltage range of 1.5V was flat, the initial capacity was 141 mAh/g, and cycle retention rate was 86%; also, redox reactions between 1.5 and 1.7V, which arose from the insertion and deintercalation of 0.005 mole of Y doping is not a case of doping because the C-rate characteristics were significantly better.

• Journal of the Korean Ceramic Society
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• v.31 no.8
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• pp.835-840
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• 1994

In this study, the synthesis of Ba2Ti9O20 powder having chemically homogeneous and highly pure fine particle size distribution was attempted by the oxalate method. And the effects of ZrO2 addition was investigated. The four compositions (X=0, 0.028, 0.048, 0.068) of Ba2(Ti9-x, Zrx)O20 were prepared by precipitation reaction of BaCl2, TiCl4, and ZrOCl2, with oxalic acid and NH4OH acting as a precipitating agent and a pH regulator respectively, in aqueous solution. In case of 4.8 mol% ZrO2 addition, the single phase Ba2Ti9O20 was obtained at 120$0^{\circ}C$ and its dielectric properties was excellent showing K=40.5, Q=4621 at 5.4 GHz.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.233-237
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• 2005

Cyclopentadiene compounds, 2-[CR'R(OMe)]-1,3-Me$_2C_5H_3$ (R, R' = 2,2'-biphenyl, 2) and 2-[CR'R(OSiMe$_3$)]-1,3-Me$_2C_5H_3$ (R, R' = 2,2'-biphenyl, 3; R = ph, R' = ph, 4; R = 2-naphthyl, R' = H, 5) are readily synthesized from 2-bromo-3-methoxy-1,3-dimethylcyclopentene (1). Reaction of the cyclopentadienes with Ti(NMe$_2$)$_4$ in toluene results in clean formation of the cyclopentadienyl tris(dimethylamido)titanium complexes, which are transformed to the trichloride complexes, 2-[CR'R(OMe)]-1,3-Me$_2C_5H_2$}TiCl$_3$ (R, R' = 2,2'-biphenyl, 6) and {2-[CR'R(OSiMe$_3$)]-1,3-Me$_2C_5H_2$}TiCl$_3$ (R, R' = 2,2'-biphenyl, 7; R = ph, R' = ph, 8; R = 2-naphthyl, R' = H, 9). Attempts to form C1-bridged Cp/oxido complexes by elimination of MeCl or Me$_3$SiCl were not successful. X-ray structures of 6, 7 and an intermediate complex {2-[Ph$_2$C(OSiMe$_3$)]-1,3-Me$_2C_5H_2$}TiCl$_2$(NMe$_2$) (10) were determined.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.148-156
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• 1993

TiN films were deposited onto high speed steel (SKH9) by plasma assisted chemical vapor deposition (PACVD) using a TiCl4/N2/H2/Ar gas mixture at around 50$0^{\circ}C$. The effects of the deposition temperature, R.F. power and TiCl4 concentration on the deposition of TiN and the microhardness of TiN film were investigated. The crystallinity and the microhardness of TiN films were improved with increase of the deposition temperature. Optimum deposition temperature in this study was 50$0^{\circ}C$, because a softening or phase transformation of the substrate occurred over 50$0^{\circ}C$. A large increase of the film growth rate with a strong(200) preferred orientation was obtained by increasing R.F. power. Much chlorine content of about 10at.% was found in the deposited films and resulted in relatively low average microhardness of about 1, 500Kgf/$\textrm{mm}^2$ compared with the theoretical value(~2, 000Kgf/$\textrm{mm}^2$).