Fabrication of N-doped titanium nanotube / reduced graphene oxide composites for photocatalytic degradation

성동범,박수진 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

In this work, N-doped titanium nanotube were prepared by sol-gel and various weight ratio of reduced graphene oxide composites by hydrothermal method for photocatalytic activities. Structural properties of the composites were characterized by X-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). The surface areas and pore size distributions were calculated by Brunauer-Emmett-Teller (BET). Photocatalytic activities were measured using rhodamine B solution under simulated solar light irradiation. Photodecomposition rate of N-TiO₂ nanotube/reduced graphene oxide composites were improved compared to pure TiO₂. The results indicated that reduced graphene oxide reduced band gap energy and decreased recombination ratio of excited electrons.

Formation and mechanistic study of self-ordered TiO₂ nanotubes on Ti substrate

Kang, S.H.,Kim, J.Y.,Kim, H.S.,Sung, Y.E. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.1

The formation of anatase TiO<SUB>2</SUB> nanotubes by anodic oxidation on a pure titanium substrate in an aqueous solution containing 0.5wt.% NaF was investigated. Nanotubes with a length of 3μm in a nanotubular TiO<SUB>2</SUB> film were obtained in the pH 4.2 electrolyte. In strong acidic solution (pH 1.5), TiO<SUB>2</SUB> nanotubes of short length were formed due to the fast chemical dissolution rate. In this case, there was no variation of the average pore diameter and wall thickness of the TiO<SUB>2</SUB> nanotubes. From this experiment, it was again confirmed that the pH value of the electrolyte controls the thickness of the well-aligned TiO<SUB>2</SUB> nanotubes. A mechanistic study of the formation of the TiO<SUB>2</SUB> nanotubes was performed based on the observation of the surface morphology (top-view and cross-sectional view) using FE-SEM and the analysis of the current density-time curves. Furthermore, the morphology of the anodized TiO<SUB>2</SUB> film shows a rough surface and irregular wall thickness, since the anodic reaction was performed in an aqueous solution containing F<SUP>-</SUP> ions. The origin of this morphology was dealt with in detail in the FE-SEM study. The crystal structure of the TiO<SUB>2</SUB> nanotubes was confirmed using XRD and Raman analyses.

Formation and mechanistic study of self-ordered TiO2 nanotubes on Ti substrate

강순형,Jae-Yup Kim,Hyun Sik Kim,성영은 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.1

The formation of anatase TiO2 nanotubes by anodic oxidation on a pure titanium substrate in an aqueous solution containing 0.5 wt.% NaF wasinvestigated.Nanotubeswithalengthof3mminananotubularTiO2lmwereobtainedinthepH4.2electrolyte.Instrongacidicsolution(pH1.5),TiO2 nanotubes of short length were formed due to the fast chemical dissolution rate. In this case, there was no variation of the average porediameter and wall thickness of the TiO2 nanotubes. From this experiment, it was again conrmed that the pH value of the electrolyte controls thethickness of thewell-aligned TiO2 nanotubes. A mechanistic study of the formation of the TiO2 nanotubes was performed based on the observationofthesurfacemorphology(top-viewandcross-sectionalview)usingFE-SEMandtheanalysisofthecurrentdensitytimecurves.Furthermore,themorphology of the anodized TiO2 lm shows a rough surface and irregular wall thickness, since the anodic reaction was performed in an aqueoussolution containing F. ions. The origin of this morphology was dealt with in detail in the FE-SEM study. The crystal structure of the TiO2nanotubes was conrmed using XRD and Raman analyses.# 2007 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Preparation and performance of polyaniline–multiwall carbon nanotubes–titanium dioxide ternary composite electrode material for supercapacitors

SINGUBALSYDULU,Umashankar Male,Palaniappan Srinivasan,윤국로 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-

Multi-walled carbon nanotubes (MWNTs), and titanium oxide (TiO2) were incorporated in polyaniline(PANI) to enhance the pseudocapacitance and cycle stability of PANI. PANI–MWNTs–TiO2, ternarycomposite was prepared by in-situ chemical polymerization of aniline in the presence of MWNTs andTiO2. Morphology analysis of ternary composite revealed the uniform covering of MWNTs by PANInanofibers and TiO2 nanoparticles. The specific capacitance of PANI–MWNTs–TiO2 is 270 F g 1, muchhigher than that of MWNTs (30 F g 1) and PANI (210 F g 1) electrodes. PANI–MWNTs–TiO2 showed goodrate capability with excellent cycling stability.

Preparation and performance of polyaniline-multiwall carbon nanotubes-titanium dioxide ternary composite electrode material for supercapacitors

Singu, B.S.,Male, U.,Srinivasan, P.,Yoon, K.R. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2017 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.49 No.-

<P>Multi-walled carbon nanotubes (MWNTs), and titanium oxide (TiO2) were incorporated in polyaniline (PANI) to enhance the pseudocapacitance and cycle stability of PANI. PANI-MWNTs-TiO2, ternary composite was prepared by in-situ chemical polymerization of aniline in the presence of MWNTs and TiO2. Morphology analysis of ternary composite revealed the uniform covering of MWNTs by PANI nanofibers and TiO2 nanoparticles. The specific capacitance of PANI-MWNTs-TiO2 is 270 Fg-1, much higher than that of MWNTs (30 Fg(-1)) and PANI (210 Fg(-1)) electrodes. PANI-MWNTs-TiO2 showed good rate capability with excellent cycling stability. (C) 2017 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry.</P>

텍스타일 형 염료감응 태양전지의 광전극 설계 및 전기적 특성분석에 관한 연구

이혜미,윤민주,김한성,Lee, Hye Mi,Yun, Min Ju,Kim, Han Seong 한국섬유공학회 2015 한국섬유공학회지 Vol.52 No.3

In this study, we designed and investigated textile-type flexible dye-sensitized solar cells (DSSCs) using titanium mesh as the photoelectrode. To improve the surface area of the $TiO_2$ photoelectrode and the performance of the DSSCs, titanium-oxide nanotubes (TNTs) were uniformly grown on the surface of the titanium mesh using anodization. The TNTs were tens of micrometers in length, which contributed to the absorption of sufficient light and effective transfer of electrons. We studied the effect of TNT growth on the DSSCs, and found that the power conversion efficiency of the DSSCs increased from 1.9% to 3.2% upon increasing the length of the TNTs on the surface of the titanium mesh.

Fabrication and Characterization of Titanium-dioxide Nanotubes Grown by Using an Electrophoretic-hydrothermal Method

임기홍,최현광 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.8

Titania (TiO2) nanotubes were grown by using a solution-based method that combined a hydrothermalprocess with an electrophoretic treatment. We prepared a Teflon autoclave for electrophoretic. hydrothermal synthesis and measured the surface morphology and the crystal structureof TiO2 by using transmission electron microscopy, X-ray diffraction, and field-emission scanningelectron microscopy. The optical properties were investigated by using photoluminescence as wellas transmittance and reflectance measurements. The synthesis technique is suitable for inexpensivemass production and for obtaining remarkable electrochemical properties such as those offered byhighly-ordered nanotube arrays. In addition to producing a homogeneous and robust film on thesurface of the substrate, particles and clusters can be aligned on the substrate surface with a desireddirection by using an applied electric field.

Electrochemical properties of TiO₂ nanotube-Li₄Ti₅O₁₂ composite anodes for lithium-ion batteries

Kim, Kwang Man,Kang, Kun-Young,Kim, Sanghyo,Lee, Young-Gi Elsevier 2012 Current Applied Physics Vol.12 No.4

<P><B>Abstract</B></P><P>For application as an anode material in lithium batteries, composite anodes consisting of TiO<SUB>2</SUB> nanotubes (TNT) and Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> (LTO) nanocrystalline particles are prepared by hydrothermal reaction of rutile TiO<SUB>2</SUB> particles, physical blending with LTO, and subsequent heat treatment at 300 °C. The TNT-LTO composites with varying the composition are characterized by electron microscopy, X-ray diffraction, potentiostatic cyclic voltammetry, and galvanostatic charge-discharge tests at various current rates. With higher LTO content, short TNTs with the average tube diameter of 10 nm are distributed among the potato-shaped LTO particles with the average diameter of 200 nm. At higher content of TNT, however, the LTO particles are sparsely distributed in the fibrillar aggregates of TNT with more lengthened image. As a result, the samples of TNT:LTO = 2:8 and 4:6 show superior cycle performance and high-rate capability, mainly due to their higher electrode densities to yield nanotubular TNT distributed on and supported by potato-shaped LTO nanoparticles.</P> <P><B>Highlights</B></P><P>► Composite anodes are prepared by hydrothermal reaction of rutile TiO<SUB>2</SUB> particles, physical blending with Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>, and subsequent heat treatment. ► The composites with varying the composition are characterized by SEM, XRD, cyclic voltammetry, and charge/discharge tests at various current rates. ► The composites of TiO<SUB>2</SUB>: Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> = 2:8 and 4:6 show superior cycle performance and high-rate capability, due to the higher electrode density.</P>

Electrochemical properties of TiO2 nanotube-Li4Ti5O12 composite anodes for lithium-ion batteries

김광만,강건영,김상효,이영기,안효준,조권구 한국물리학회 2012 Current Applied Physics Vol.12 No.4

For application as an anode material in lithium batteries, composite anodes consisting of TiO2 nanotubes (TNT) and Li4Ti5O12 (LTO) nanocrystalline particles are prepared by hydrothermal reaction of rutile TiO2particles, physical blending with LTO, and subsequent heat treatment at 300 ℃. The TNT-LTO composites with varying the composition are characterized by electron microscopy, X-ray diffraction, potentiostatic cyclic voltammetry, and galvanostatic charge-discharge tests at various current rates. With higher LTO content, short TNTs with the average tube diameter of 10 nm are distributed among the potato-shaped LTO particles with the average diameter of 200 nm. At higher content of TNT, however, the LTO particles are sparsely distributed in the fibrillar aggregates of TNT with more lengthened image. As a result, the samples of TNT:LTO = 2:8 and 4:6 show superior cycle performance and high-rate capability, mainly due to their higher electrode densities to yield nanotubular TNT distributed on and supported by potatoshaped LTO nanoparticles.

The Bioactivity of Enhanced Ti-32Nb-5Zr Alloy with Anodic Oxidation and Cyclic Calcification

Park, Il-Song,Bae, Tae-Sung Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.8

Nanotubes form highly compact structures of small diameter tubes in between relatively larger diameter tubes, and have a structure of hollow tubes with connected outer walls. An even calcium phosphate layer was formed on the surface of the nanotube layer by alternative immersion treatment (AIT). The precipitated calcium phosphate formed a bite with the surface of the vesicular structure and was combined as penetration occurred inside the nanotubes. Hydroxyapatite (HAp) precipitation of Ti-32Nb-5Zr alloy treated with AIT rapidly accelerated under the environment of simulated body fluid. When implanted into the tibias of a rat, the bonding strength of bone and the amount of newly formed bone were greatly enhanced. This demonstrates that the bioactivity of <TEX>${\beta}$</TEX>-type Ti-32Nb-5Zr alloy could be enhanced through the formation of a <TEX>$TiO_2$</TEX> layer and cyclic calcification in a solution containing phosphate and calcium ions.