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Fabrication, Modification, and Emerging Applications of TiO2 Nanotube Arrays by Electrochemical Synthesis: A Review  [PDF]
Jian-Ying Huang,Ke-Qin Zhang,Yue-Kun Lai
International Journal of Photoenergy , 2013, DOI: 10.1155/2013/761971
Abstract: Titania nanotube arrays (TNAs) as a hot nanomaterial have a unique highly ordered array structure and good mechanical and chemical stability, as well as excellent anticorrosion, biocompatible, and photocatalytic performance. It has been fabricated by a facile electrochemical anodization in electrolytes containing small amounts of fluoric ions. In combination with our research work, we review the recent progress of the new research achievements of TNAs on the preparation processes, forming mechanism, and modification. In addition, we will review the potential and significant applications in the photocatalytic degradation of pollutants, solar cells, water splitting, and other aspects. Finally, the existing problems and further prospects of this renascent and rapidly developing field are also briefly addressed and discussed. 1. Introduction Nanostructured materials with peculiar properties are not expected in bulk phase and have already led to a breakthrough in various fields of science and technology. Moreover, much of the current interest in one-dimensional nanostructures, such as nanotube, nanowire, nanorod, and nanobelts, was initiated by the discovery of carbon nanotubes by Iijima et al. in 1991 [1]. Within these nanostructure materials, TiO2-based nanotubes attracted engrossing interest and intensive researches due to their merits of high specific surface area, ion-changeable ability, and photocatalytic ability. Over the past decades, nanostructured materials derived from TiO2 have extensively been investigated for many promising applications, including solar cells/batteries, self-cleaning coatings, electroluminescent hybrid devices, and photocatalysis, owing to their peculiar chemical and physical behaviors. Currently, developed methods of fabricating TiO2-based nanotubes comprise the assisted-template method [2, 3], hydrothermal treatment [4–6], and electrochemical anodic oxidation [7–10]. Each fabrication method has unique advantages and functional features and comparisons among these approaches. Regarding the template-assisted method, anodic aluminum oxide (AAO) nanoporous membrane, which consists of an array of parallel straight nanopores with controllable diameter and length, is usually used as template. However, the template-assisted method often encounters difficulties of prefabrication and postremoval of the previous templates and usually results in impurities. Concerning hydrothermal treatment, the self-assembled TiO2 nanotubes are based on the treatment of Ti foils or TiO2 powders in a tightly closed vessel containing highly concentrated
TiO2纳米管电极上电化学还原CO2生成CH3OH
Electrochemical Reduction of CO2 to Methanol at TiO2 Nanotube Electrodes
 [PDF]

裘建平,童怡雯,赵德明,何志桥,陈建孟,宋爽,()
- , 2017, DOI: 10.3866/PKU.WHXB201704078
Abstract: 采用原位阳极氧化-煅烧法制备TiO2纳米管(TiO2NTs)电极,运用X射线衍射(XRD)、电场发射扫描电子显微镜(FESEM)、X射线光电子能谱(XPS)、双电位阶跃测试等对制备电极进行表征,考察了其在0.1 mol·L-1 KHCO3水溶液中电化学还原CO2的催化活性。结果表明TiO2NTs电极上电化学还原CO2的主产物为CH3OH,CH3OH由HCOOH和HCHO进一步还原而来。电极制备的最佳煅烧温度为450℃(TiO2NTs-450),电解电位-0.56 V(vs RHE(可逆氢电极))时反应120 min后,生成CH3OH的法拉第效率和分电流密度分别为85.8%和0.2 mA·cm-2。与550和650℃煅烧的电极相比,TiO2NTs-450电极具有更高的催化活性,归因于电极表面更多的三价钛活性位,有利于CO2吸附,从而对·CO2-起到稳定的作用,速率控制步骤转变为·CO2-的质子化反应。
A series of highly ordered TiO2 nanotube (TiO2NTs) electrodes are prepared via potentiostatic anodization of Ti foil followed by calcining in air. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and potential steps determination are used to characterize the electrodes. The electrochemical reduction of CO2 on these three TiO2NTs electrodes is investigated by cyclic voltammetry and potentiostatic electrolysis in 0.1 mol·L-1 KHCO3 aqueous solution. Methanol is found to be the major product in electrochemical CO2 reduction, while formic acid, formaldehyde, methane, and CO are formed as minor products. Compared with the electrodes sintered at 550 and 650℃, the optimal TiO2NTs electrode is found to be the one calcined at 450℃ (TiO2NTs-450). After 120 min of reaction, the Faradaic efficiency and partial current density of methanol is 85.8% and 0.2 mA·cm-2 at -0.56 V vs. reversible hydrogen electrode (RHE), respectively. The trivalent titanium in TiO2 serves as an efficient site for adsorption of CO2 and stabilization of the adsorbed ·CO2- radical. Consequently, the reduction of CO2 on TiO2NTs electrodes involves a fast first electron and proton transfer followed by a slow second proton transfer as the rate-limiting step
Tunable Fabrication of TiO2 Nanotube Arrays with High Aspect Ratio and its Application in Dye Sensitized Solar Cell
WU Cong-Cong,ZHUO Yan-Jun,ZHU Pei-Ning,CHI Bo,PU Jian,LI Jian
无机材料学报 , 2009, DOI: 10.3724/sp.j.1077.2009.00897
Abstract: TiO2 nanotube arrays were fabricated by anodization of titanium foils in the viscous nonaqueous electrolytes. Effects of anodization parameters on TiO2 nanotube were intensively studied. The photo-electrochemical property of dye sensitized solar cell (DSSC) based on TiO2 nanotube arrays was tested and the influence of TiO2 nanotube morphology on the performance of DSSC was investigated. The result indicates that the growth of TiO2 nanotube arrays with high aspect ratio depends highly on the nonaqueous solution which is enhanced by the applied potential and anodizing time. TiO2 nanotube arrays with aspect ratio up to 313.6 are fabricated in 0.5wt%NH4F in glycerol glycol at 50V for 17h. DSSC based on TiO2 nanotube arrays (fabricated in 0.5wt%NH4F in glycerol at 40V for 13h)exhibits an open circuit potential of 0.723V, 2.15mA/cm2 short circuit current density.
Photoelectrocatalytic Performance of Ag/TiO2-xNx Nanotube  [PDF]
WAN Bin,CHEN Ming-Bo,ZHOU Xi-Ying,WANG Wei,LI Wen-Ge
无机材料学报 , 2010, DOI: 10.3724/sp.j.1077.2010.00285
Abstract: High density, well ordered,vertically aligned and uniform titanium oxide nanotube arrays were fabricated on the surface of pure titanium sheet by direct electrochemical anodic oxidation under 20V in electrolyte of 0.5wt%NaF +1mol/L Na2SO4. Then TiO2 nano-tube array were annealed in ammonia for 2h, Ag nano-particles were deposited photocatalytically on the N-doped TiO2 nanotube surface. XRD, SEM and XPS techniques were used to characterize titanium oxide nanotube arrays. Results show that photoelectrondegradation efficiency of Ag/TiO 2-x Nx nano-tubes under UV-light is about 39.68% higher than that of TiO2 nanotubes; and photoelectrodegradation efficiency of Ag/TiO 2-x Nx nano-tubes under visible light is 12% higher than that of TiO2 nano-tubes. After photoelectrondegradation under visible hight for 16h, the degradation rate of mathylene blue with initial concentration of 10×10-6 mol/L is 50.53%.
TiO2 Nanotube Based Dye-sensitized Photoanode  [PDF]
LUO Hua-Ming, LIU Zhi-Yong, BAI Chuan-Yi, LU Yu-Ming, CAI Chuan-Bing
无机材料学报 , 2013, DOI: 10.3724/sp.j.1077.2013.12368
Abstract: A front-illuminated TiO2 nanotube-based dye-sensitized solar-cell (DSC) was presented. Highly ordered TiO2 nanotube membranes were fabricated by two-step anodic oxidation of Ti foil, and then they were transferred to fluorine-doped tin oxide glass substrates to produce a special kind of photoanode. A series of comparison were made between DSCs with different length of nanotubes. Front-illuminated DSC with 32.8 μm nanotube membrane showed an efficiency of 4.15% with TiCl4 treatment. The crystal phase evolution of the TiO2 nanotubes was researched using X-Ray Diffraction (XRD). Electrochemical Impedance Spectra (EIS) results indicated that the electron transportation efficiency had a strong dependence on the thickness of photoanode, and interfacial resistances decreased with the increasing of nanotubes length. These results could help us to understand the mechanism of the electron transportation and further improve the photoanode of DSCs.
Synthesis and Electrochemical Performance of TiO2/C Nanocomposites  [PDF]
JIN Shuang-Ling, DENG Hong-Gui, ZHAN Liang, ZHAO Yue, QIAO Wen-Ming, LING Li-Cheng
无机材料学报 , 2012, DOI: 10.3724/sp.j.1077.2012.11527
Abstract: TiO2/C nanocomposites with diameter of 300-400 nm were synthesized through hydrothermal reaction from titanium glycolate spheres with glucose as carbon precursor. The effects of the glucose concentration on the morphology, structure and carbon coating and electrochemical performance of the product were investigated. When the carbon content of TiO2/C nanocomposite was 7wt%, its average crystallite size, BET surface area and average pore size were 7.1 nm, 157 m2/g and 5.2 nm, respectively. When the TiO2/C nanocomposites is used as anode materials for lithium-ion battery, it delivered a capacity of 160 mAh/g after 80 charge/discharge cycles at a current rate of 0.2C with a good rate capability.
Tunable Fabrication of TiO2 Nanotube Arrays with High Aspect Ratio and its Application in Dye Sensitized Solar Cell
高长径比TiO2纳米管阵列的调控制备及其光阳极性能

WU Cong-Cong,ZHUO Yan-Jun,ZHU Pei-Ning,CHI Bo,PU Jian,LI Jian,
吴聪聪

无机材料学报 , 2009,
Abstract: TiO2 nanotube arrays were fabricated by anodization of titanium foils in the viscous nonaqueous electrolytes. Effects of anodization parameters on TiO2 nanotube were intensively studied. The photo-electrochemical property of dye sensitized solar cell (DSSC) based on TiO2 nanotube arrays was tested and the influence of TiO2 nanotube morphology on the performance of DSSC was investigated. The result indicates that the growth of TiO2 nanotube arrays with high aspect ratio depends highly on the nonaqueous solution which is enhanced by the applied potential and anodizing time. TiO2 nanotube arrays with aspect ratio up to 313.6 are fabricated in 0.5wt%NH4F in glycerol glycol at 50V for 17h. DSSC based on TiO2 nanotube arrays (fabricated in 0.5wt%NH4F in glycerol at 40V for 13h)exhibits an open circuit potential of 0.723V, 2.15mA/cm2 short circuit current density.
Graphene/Polypyrrole Nanocomposite as Electrochemical Supercapacitor Electrode: Electrochemical Impedance Studies  [PDF]
Punya A. Basnayaka, Manoj K. Ram, Lee Stefanakos, Ashok Kumar
Graphene (Graphene) , 2013, DOI: 10.4236/graphene.2013.22012
Abstract: Graphene-Polypyrrole (G/PPy) was synthesized by chemical oxidative polymerization method, and electrochemical impedance spectroscopy (EIS) analysis was employed to study the frequency response characteristics of supercapacitors based on G/PPy conducting polymer nanocomposite. It is found that a uniform G/PPy nanocomposite is formed with polypyrrole (PPy) being homogeneously surrounded by graphene nanosheets. The porous structure allowed electrolyte and ions diffusion in synthesized G/PPy nanocomposite. The metallic conductivity of Graphene-polypyrrole exhibited higher knee frequency at 125 Hz than the knee frequency of pristine PPy at 36 Hz. The high knee frequency of G/PPy supercapacitor is indicative of high power application and long cycle life. The G/PPy nanocomposite based supercapacitor with 1MH2SO4 as the electrolyte showed specific capacitances of 270 F/g at 0.1 Hz and112 F/g at 125 Hz.
Quasi Solid-State Dye-Sensitized Solar Cell Incorporating Highly Conducting Polythiophene-Coated Carbon Nanotube Composites in Ionic Liquid  [PDF]
Mohammad Rezaul Karim,Ashraful Islam,Surya Prakash Singh,Liyuan Han
Advances in OptoElectronics , 2011, DOI: 10.1155/2011/357974
Abstract: Conducting polythiophene (PTh) composites with the host filler multiwalled carbon nanotube (MWNT) have been used, for the first time, in the dye-sensitized solar cells (DSCs). A quasi solid-state DSCs with the hybrid MWNT-PTh composites, an ionic liquid of 1-methyl-3-propyl imidazolium iodide (PMII), was placed between the dye-sensitized porous TiO2 and the Pt counter electrode without adding iodine and higher cell efficiency (4.76%) was achieved, as compared to that containing bare PMII (0.29%). The MWNT-PTh nanoparticles are exploited as the extended electron transfer materials and serve simultaneously as catalyst for the electrochemical reduction of I ? 3 . 1. Introduction Dye-sensitized solar cells (DSCs) have attracted significant attention as promising solar-to-electricity power conversion devices because of their higher energy conversion and potential for low-cost production [1–6]. In general, DSCs comprise an electrode consisting of nanocrystalline titanium dioxide (TiO2) films modified with a dye, a platinum counterelectrode, and an electrolyte solution in between the electrodes. Photoexcitation of the dye results in the injection of an electron into the conduction band of the oxide. The original state of the dye is subsequently restored by electron donation from a redox system, such as the iodide/triiodide (I?/I3??) couple. At the present, DSCs are mainly constructed by using liquid electrolyte as a charge transport material. The charge transport in these liquid electrolytes is typically achieved by using I?/I3?? redox reaction in electrolyte solution. Therefore, long-term durability of DSCs is limited by leakage and the volatilization of organic solvent-based electrolytes. Numerous investigations have been conferred to overcome this drawback, replacing the liquid electrolyte by organic and inorganic hole transport materials [7–9], polymer and gel electrolytes [10–14], and nanocomposite ionic liquid (IL) electrolytes [15–20] resulting in solid-state and quasi solid-state DSCs. Imperfect pour filling of the dye-coated nanocrystalline TiO2 film with organic and inorganic hole transport materials results in a poor device efficiency. Moreover, the ionic conductivity for the majority of the amorphous polymer electrolytes is too low (<10?5?S?cm?1), limiting the device efficiency. Although nanocomposite IL electrolyte can reduce leakages, it is not satisfactory, because of the high concentration of corrosive and volatile iodine present in the electrolyte. The introduction of I2 into the electrolytes could increase the conductivity of the electrolyte
Electropolymerized Coatings of Poly (o-anisidine) and Poly (o-anisidine)-TiO2 Nanocomposite on Aluminum Alloy 3004 by using the Galvanostatic Method and Their Corrosion Protection Performance  [cached]
Shabani-Nooshabadi M.,Jafari Y.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: Poly (o-anisidine) (POA) and also poly (o-anisidine)-TiO2 (POA-TiO2) nanocomposite coatings on aluminum alloy 3004 (AA3004) have been investigated by using the galvanostatic method. The electrosynthesized coatings were characterized by FT-IR, SEM- EDX, SEM and AFM. The corrosion protection performances of POA and also POA-TiO2 nanocomposite coatings were investigated in 3.5% NaCl solution by using the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The corrosion rate of nanocomposite coatings was found ~900 times lower than bare AA3004. The results of this study clearly ascertain that the POA-TiO2 nanocomposite has outstanding potential to protect the AA3004 against corrosion.
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