• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1613-1616
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• 2012

Ni nanoparticles-$TiO_2$ nanotube arrays (Ni/$TiO_2NTs$) composites were prepared by pulsed electrodeposition method and subsequently characterized by means of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The FESEM results showed that highly dispersed Ni nanoparticles were not only loaded on the top of the $TiO_2NTs$ but also within the tubular structure, and the particle size of Ni prepared at different current amplitude (100, 200 and 300 $mA{\cdot}cm^{-2}$) was in the range of 15 to 70 nm. The electrochemical studies indicated that Ni nanoparticles loaded on the highly ordered $TiO_2NTs$ are readily accessible for electrochemical reactions, which improve the efficiency of the Ni nanoparticles and $TiO_2NTs$. A maximum specific capacitance (27.3 $mF.cm^{-2}$) was obtained on the Ni/$TiO_2NTs$ composite electrode that prepared at a current of 200 $mA.cm^{-2}$, and the electrode also exhibited excellent electrochemical stability.

• Journal of Powder Materials
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• v.18 no.1
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• pp.56-63
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• 2011

Recently, $TiO_2$ nanotubes have considerably researched because of their novel application about photocatalysis, dye-sensitized solar cells (DSSCs), lithium ion battery, etc. In this work, self-standing $TiO_2$ nanotube arrays were fabricated by anodic oxidation method using pure Ti foil as a working electrode in ethylene glycole with 0.3M $NH_4F$ + $2%H_2O$. Growth behavior of $TiO_2$ nanotube arrays was compared according to temperature, voltage and time. The morphology, structure and crystalline of anodized $TiO_2$ nanotube arrays were observed by FE-SEM (field emission scanning electron microscope) and XRD (X-ray diffraction).

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1981-1987
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• 2010

A novel composite (Ag-CNT/$TiO_2$) of silver treated carbon nanotubes (Ag-CNT) and $TiO_2$ was synthesized via wet chemistry followed by a heat treatment. The dispersion and structure of the silver in the synthesized composites determined by X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy(TEM). XRD patterns of the composites showed that the composites contained a mixing anatase and rutile phase. The EDX spectra showed the presence of C, O, Ti and Ag peaks. The $TiO_2$ particles were distributed uniformly in the CNT network, and silver particles were virtually fixed on the surface of the tube. The photocatalysis degraded behaviors of the Ag-CNT/$TiO_2$ composites of the methylene blue, which increased with an increase of the silver component. The Ag-CNT/$TiO_2$ composites have excellent antibacterial activities against Escherichia coli (E. Coli), Pseudomonas aeruginosa (P. Aeru) and Bacillus subtilis (B. Sub) under visible light.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.14-19
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• 2010

Partial anodic oxidation of Ti-mesh with a wire diameter of ~200[${\mu}m$] produces self-aligned $TiO_2$ nanotube arrays (~50[${\mu}m$] in length) on Ti-mesh substrate. The electrolyte used for anodic oxidation was an ethylene glycol solution with an addition of 1.5 vol. % $H_2O$ and 0.2 wt. % $NH_4F$. A dye-sensitized solar cell utilizing the photoanode structure of $TiO_2$-nanotube/Ti-mesh was fabricated without a transparent conducting oxide (TCO) layer, in which Ti-mesh replaced the role of TCO. The 1.93[%] photoconversion efficiency was low, which can be attributed to both insufficient dye molecules attachment and limited electrolyte flow to dye molecules. The optimized nanotube diameter and length as well as the $TiCl_4$ treatment can improve cell performance.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.511-517
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• 2012

Pd/MWCNT/$TiO_2$ composites were synthesized by a sol-gel technique using multi-walled carbon nanotubes (MWCNT), palladium (II) chlorite ($PdCl_2$) and titanium tetrachloride ($TiCl_4$) as the carbon, palladium and titanium precursors. The Pd/MWCNT/$TiO_2$ composites prepared were characterized by BET surface area measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activity of the composites was evaluated using the degradation of methylene blue (MB) under UV and visible light irradiation as a model.

• Korean Journal of Materials Research
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• v.17 no.8
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• pp.437-441
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• 2007

Preparation and morphology control of $TiO_2$ nano powders for gas sensor applications are investigated. $TiO_2$ nanopowders with rutile and anatase structures were prepared by controlling the pH value of a precursor solution without any heat treatment. The mean particle size of $TiO_2$ powders were below 10nm. The prepared $TiO_2$ nano powders were hydrothermal treated by NaOH solution. The sample was washed in HCl solution. As a result and $TiO_2$ nanotubes were formed. The lengths of $TiO_2$ nanotube were $1{\mu}m$ and the diameters were 10nm. Crystal structure and microstructure of $TiO_2$ nanotube were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). As-prepared $TiO_2$ nanotube powders have several advantages of nano particle size and high surface area and could be a prominent candidate for nano-sensors. The sensitivity of $TiO_2$ nanotube sensor was measured for toluene and NO in this study.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.58-62
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• 2010

CNT-$TiO_{2}$ nano complexes were prepared from $TiOSO_4$ and multi-walled carbon nanotube (MWCNT) by hydrolysis. The CNTs were dispersed uniformly with anatase $TiO_{2}$ in the prepared $TiO_{2}$-CNT complexes. The increasing MWCNT ratio leads to increased crystalline carbon and O/Ti ratio. The decomposition degree of methylene blue was experienced according to UV radiation time for study adsorption and photocatalytic activity. The samples having high MWCNT ratio show high adsorption and photodegradation. The high specific surface area, functional group having oxygen, low band gap energy, high electric conductivity, high volume to surface ratio, uniform structure and properties of MWCNT assist photocatalytic activity of CNT-$TiO_{2}$ complex.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.345-350
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• 2010

For the present paper, we prepared MgO/MWCNT/$TiO_2$ photocatalyst by using multi-walled carbon nanotubes (MWCNTs) pre-oxidized by m-chlorperbenzoic acid (MCPBA) with magnesium acetate tetrahydrate $(Mg(CH_2COO)_2\cdot4H_2O)$ and titanium n-butoxide $(Ti\{OC(CH_3)_3\}_4)$ as magnesium and titanium precursors. The prepared photocatalyst was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The decomposition of methylene blue (MB) solution was determined under irradiation of ultraviolet (UV) light. The XRD results show that the MgO/MWCNT/$TiO_2$ photocatalyst have cubic MgO structure and anatase $TiO_2$ structure. The porous structure and the $TiO_2$ agglomerate coated on the MgO/MWCNT composite can be observed in SEM images. The Mg, O, Ti and C elements can be also observed in MgO/MWCNT/$TiO_2$ photocatalyst from EDX results. The results of photodegradation of MB solution under UV light show that the concentration of MB solution decreased with an increase of UV irradiation time for all of the samples. Also, the MgO/MWCNT/$TiO_2$ photocatalyst has the best photocatalytic activity among these samples. It can be considered that the MgO/MWCNT/$TiO_2$ photocatalyst had a combined effect, the effect of MWCNT, which could absorb UV light to create photoinduced electrons $(e^-)$, and the electron trapping effect of MgO, which resulted in an increase of the photocatalytic activity of $TiO_2$.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.76-82
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• 2014

1-Methylimidazole-2-thiol, as a kind of mercaptans, is a typical organic pollutant which has not been efficiently removed. In this study, titanium dioxide ($TiO_2$) photocatalyst based on magnetic multi-walled carbon nanotubes (MWCNTs) was synthesized via hydrothermal and sol-gel methods. The as-prepared photocatalyst was extensively characterized by X-ray diffraction (XRD), X-ray energy diffraction spectrum (EDS), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectra, UV-Vis diffuse reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM). This photocatalyst of $TiO_2$/$Fe_3O_4$/MWCNTs was proved to exhibit high photocatalytic efficiency and the photodegradation rate could reach nearly 82.7% for the degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation. In addition, the results demonstrated that inorganic ions had a negative impact on photodegradation of 1-methylimidazole-2-thiol to varying degrees. Moreover, pH had a great and complex effect on photocatalytic degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.282-286
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• 2009

The synthesis and characterization of catalysts supported on multi-walled carbon nanotubes (CNTs). $Pt/Au/TiO_2$ is added to a CNTs(cabon nano tube) carbon support to improve the performance of a direct methanol fuel cell. XRD and SEM showed that uniform anatase $TiO_2$ and Pt/Au particles were about 200 nm and 20${\sim}$25 nm in diameter. The composite catalyst activities were measured by cyclic voltammetry (CV), demonstrating that it is more promising for use in fuel cells.