TiO2纳米管阵列膜的制备及对304不锈钢的光生阴极保护效应

应用电化学阳极氧化法在Ti表面构筑不同的TiO2纳米管阵列膜。采用XRD、SEM、XPS表征薄膜的结构、形貌和组成。通过电化学阻抗谱及电位随时间变化的测试,考察TiO2薄膜的光生阴极保护效应。结果表明薄膜主要由锐钛矿型的TiO2纳米管阵列组成,当304不锈钢耦连于紫外光照下的TiO2薄膜电极时,其界面反应电阻变小,电极电位显著降低,说明TiO2纳米管薄膜能够对不锈钢产生良好光生阴极保护效应,特别是掺Fe的TiO2薄膜在光照时可使不锈钢电位降低约450mV,而且在暗态时也能较长时间保持对不锈钢的阴极保护作用。     

Bi2S3-modified TiO2 nanotube arrays: easy fabrication of heterostructure and effective enhancement of photoelectrochemical property

A novel heterostructure of Bi₂S₃ nanoparticles (NPs) and TiO₂ nanotube arrays (NAs) was fabricated by a conventional hydrothermal method. The morphological features and the X-ray diffractogram of the obtained Bi₂S₃/TiO₂ NAs were characterized by field-emission scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The photoelectrochemical property of Bi₂S₃/TiO₂ NAs was also evaluated. The results demonstrated that photoelectrochemical solar cells based on Bi₂S₃/TiO₂ NAs had a short-circuit current of 4.54 mA/cm² and photoelectric conversion efficiency of 1.86 %. Surface photovoltage spectroscopy and field-induced surface photovoltage spectroscopy data indicated the existence of a strong interfacial electronic field between the two components Bi₂S₃ NPs and TiO₂ NAs, which can enhance the separation of photogenerated charge carriers.     

Ti O2纳米管阵列基底退火温度对CdSe/Ti O2异质结薄膜光电化学性能的影响

通过电化学沉积法以TiO2纳米管阵列(TNTs)为基底制备CdSe/TiO2异质结薄膜。研究TiO2纳米管阵列基底不同退火温度(200,350,450,600℃)对CdSe/TiO2异质结薄膜光电化学性能的影响。采用SEM,XRD,UV-Vis,电化学测试等方法对样品的微观形貌、晶体结构、光电化学性能等进行表征。结果表明:立方晶型的CdSe纳米颗粒均匀沉积在TiO2纳米管阵列管口及管壁上。TiO2纳米管阵列未经退火及退火温度为200℃时,为无定型态,在TiO2纳米管阵列上沉积的CdSe纳米颗粒数量少,尺寸小,异质结薄膜光电性能较差,光电流几乎为零。随着退火温度升高到350℃,TiO2纳米管阵列基底开始向锐钛矿转变;且沉积在TiO2纳米管上的CdSe颗粒增多,尺寸增大,光电化学性能提高。退火温度为450℃时光电流值达到最大,为4.05mA/cm^2。当退火温度达到600℃时,TiO2纳米管有金红石相出现,CdSe颗粒变小,数量减少,光电化学性能下降。     

Enhanced photoelectrochemical current response of titania nanotube array

Self-organized and highly-ordered TiO₂ nanotube array with disjunctive wall-hole structure has been synthesized from titanium foil by potentiostatic–galvanostatic anodization process. The morphology and microstructure of the TiO₂ layer depend greatly on the electrolyzing parameters and electrolyte components. TiO₂ formation mechanism by anodization oxidation is discussed. The crystallized TiO₂/Ti nanotube electrode exhibited a significant enhancement of photoelectrochemical current response in comparison with micrometer-sized TiO₂/Ti multiporous electrode. Such kind of TiO₂ nanotube will have many potential applications in various areas as an outstanding photoelectrochemical material.     

Photocatalytic microreactor using anodized TiO2 nanotube array

Photocatalytic microreactor using an anodized TiO₂ nanotube/Ti bi-layered plate was fabricated. The inner diameter and length of TiO₂ nanotube were controllable by the anodization voltage and time. The photocatalytic reduction of p-nitrophenol was conducted in the microreactor. The experimental results were well fitted by a model assuming parabolic velocity profile and zero-order kinetics of surface reaction. The photocatalytic activity of TiO₂ nanotube was enhanced as the surface area was increased by anodization voltage and time.     

Novel photodetectors based on double-walled carbon nanotube film/TiO2 nanotube array heterodimensional contacts

A new kind of photodetector based on a double-walled carbon nanotube (DWCNT) film and a TiO₂ nanotube array with hetrodimensional non-ohmic contacts has been fabricated. Due to the dimensionality difference effect, the DWCNT film/TiO₂ nanotube array photodetector exhibits a much higher photocurrent-to-dark current ratio and photoresponse relative to an Au film/TiO₂ nanotube array device, even at small bias voltage. The photocurrent-to-dark current ratio reached four orders of magnitude and a high photoresponse of 2467 A/W was found upon irradiation at 340 nm. Furthermore, the photosensitive regions could be extended into the visible range. The photocurrent-to-dark current ratio reached approximately three orders of magnitude upon irradiation at 532 nm, where the photon energy is much lower than the band gap of TiO₂.      

阳极氧化法制备TiO2纳米管及特性研究

采用单向直流脉冲电源阳极氧化方法,在乙二醇 0.5%(wt)NH4F的电解质溶液中,在电压为40～60V之间制备了直径为90～142nm、管壁厚度为21.8～17nm的TiO2纳米管.对阳极氧化过程中加入和不加超声波辅助条件进行了对比实验.通过对试样的SEM测试和阳极氧化过程中数字万用表不间断采集得到的平均电流表明,TiO2纳米管的形貌、生长速度密切依赖于氧化处理的电参数和超声波辅助源.同时通过XRD和UV-Vis等检测手段对TiO2纳米管退火前后的特性进行了研究.     

Visible light photoelectrochemical performance of W-loaded TiO2 nanotube arrays: structural properties

Well aligned TiO2 nanotubes were successfully synthesized by anodization of Ti foil at 60 V in a fluorinated bath comprised of ethylene glycol with 5 wt% of NH4F and 5 wt% of H2O2. In order to enhance the visible light absorption and photoelectrochemical response of pure TiO2 nanotube arrays, a mixed oxide system (W-TiO2) was investigated. W-TiO2 nanotube arrays were prepared using radio-frequency (RF) sputtering to incorporate the W into the lattice of TiO2 nanotube arrays. The W atoms occupy the substitutional position within the vacancies of TiO2 nanotube arrays. The as-anodized TiO2 is amorphous in nature while the annealed TiO2 is anatase phase. The mixed oxide (W-TiO2) system in suitable TiO2 phase plays important roles in efficient electron transfers due to the reduction in electron-hole recombination. In this article, the effect of the sputtered W into the as-anodized/annealed TiO2 nanotube arrays on the photoelectrochemical response was presented.     

A photoelectrochemical study of CdS modified TiO2 nanotube arrays as photoanodes for cathodic protection of stainless steel

An electrodeposited CdS nanoparticles-modified highly-ordered TiO₂ nanotube arrays (CdS-TNs) photoelectrode and its performance of photocathodic protection are reported. The self-organized TiO₂ nanotube arrays are fabricated by electrochemical anodization in an organic-inorganic mixed electrolyte and sensitized with CdS nanoparticles by electrodeposition via a single-step direct current. The morphology, crystalline phase, and composition of the CdS-TNs films were characterized systematically by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy, respectively. The photoelectrochemical performances of the CdS-TNs film under illumination and dark conditions in 0.5 M NaCl solution were evaluated through the electrochemical measurements. It is indicated that the TNs incorporated by CdS effectively harvest solar light in the UV as well as the visible light (up to 480 nm) region. It is supposed that the high photoelectro-response activity of the CdS-TNs is attributed to the increased efficiency of charge separation and transport of electrons. The electrode potentials of 304 stainless steel coupled with the CdS-TNs is found to be negatively shifted for about 246 mV and 215 mV under UV and white light irradiation, respectively, which can be remained for 24 h even in darkness. It is implied that the CdS-TNs are able to effectively function a photogenerated cathodic protection for metals both under the UV and visible light illumination.     

Electrochemiluminescence cell fabrication using TiO2 nanotube produced by anodic oxidation

Electrochemiluminescence (ECL) cell using the electrode of TiO2 nanotube (NT) and Ru(ll) complex Ru(bpy)3(PF6)2 as a luminacence substance was fabricated. TiO2 NT were produced from the membrane of TiO2 NT arrays fabricated by anodic oxidation of approximately 100 microm thick Ti-plate. TiO2 NT arrays inject increasing number of electrons to the Ru(II) complex at the interface of TiO2 NTs. It allows the increasing exergonic oxidation/reduction reaction of Ru(II) complex. The ECL cell emits approximately 600 nm light in orange color. The cell structure is composed of a glass/F-doped SnO2(FTO)/TiO2 NT/Ru(II) complex in propylene carbonate/FTO/glass. The ECL efficiency of the cell consisting of the layer of TiO2 NT was approximately 255 cd/m2 at a bias of 4 V. The use of TiO2 NT increases ECL intensities by 5 times compared to the typical ECL cell without the use of TiO2 NT.     

Preparation and photocatalytic activity of N-doped TiO2 nanotube array films

The N-doped TiO₂ nanotube array films were fabricated directly by one-step electrochemical anodic oxidation of Ti foils in an HF electrolyte containing ammonium and nitrate ions. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDX), and ultraviolet–visible (UV–vis) absorption spectroscopy, respectively. The photocatalytic activities were evaluated by the degradation of methyl orange (MO) under visible light irradiation. The results showed that N dopant was successfully introduced into the TiO₂ nanotube array films. The N-doped TiO₂ nanotube array films showed a red shift and an enhancement of the absorption in the visible light region compared to the undoped sample. The photocatalytic activities of the N-doped TiO₂ samples were much higher than those of the undoped sample. A maximum enhancement of photocatalytic activity was achieved for the N-doped TiO₂ sample prepared in 0.07 M HF electrolyte containing 1.0 M NH₄NO₃, and 81% of MO was degraded in 150 min under visible light irradiation.     

Influence of secondary anodization voltage on free-standing crystallized TiO2 nanotube array membrane

Vertically aligned, free-standing crystallized TiO₂ nanotube arrays with a length of 32 μm have been fabricated by a two-step anodization method. The TiO₂ nanotube membrane can be detached from the Ti substrate through the secondary anodization process. The influence of the secondary anodization voltage on the morphology, crystalline phase and photovoltaic performance of the as-fabricated samples has been investigated. Results show that the side wall of TiO₂ nanotubes becomes obviously thin as the secondary anodization voltage increases and leads to crack when the voltage reaches 25 V. The mass fraction of the anatase reduces by the increase of the voltage. Furthermore, the dye-sensitized solar cells (DSSCs) based on TiO₂ nanotube arrays have been assembled. The energy conversion efficiency decreases with the increase of secondary anodization voltage, and a highest energy conversion efficiency of 10.6 % under UV illumination (368.1 nm) is obtained from the cell with TiO₂ nanotube membrane re-anodizad at 15 V.     

TiO2纳米管阵列催化降解甲基橙的性能研究

采用阳极氧化法制备了TiO2纳米管阵列电极,以甲基橙为目标降解物研究了TiO2纳米管阵列电极的光催化和光电催化性能.此外,还进行了超声辐射替代紫外光照探索性研究.结果表明,阳极氧化时间和热处理温度对TiO2纳米管阵列电极的光催化性能具有显著影响;在光催化过程中,施加一定外加电压可有效提高电极的光催化活性.尽管与紫外光照相比,超声辐射在TiO2纳米管阵列电极的催化氧化甲基橙分子过程中的促进作用具有一定的差距,但仍显示出替代紫外光照的可行性.     

Reduced graphene oxide-based photocatalysts containing Ag nanoparticles on a TiO2 nanotube array

A simple one-step electrochemical deposition method was demonstrated to fabricate reduced graphene oxide/Ag nanoparticle co-decorated TiO₂ nanotube arrays (RGO/Ag–TiO₂NTs) photocatalyst in this study. The structures and properties of these photocatalysts were characterized using scanning electron microscope, X-ray diffraction, UV–Vis diffuse reflection spectra, and photoluminescence. By taking the advantages of TiO₂, graphene, and Ag nanoparticles (AgNPs), RGO/Ag–TiO₂NTs showed a greatly improved photocatalytic activity compared with the bare TiO₂NTs, Ag–TiO₂NTs or RGO–TiO₂NTs. The deposited RGO and AgNPs not only reduce the recombination of photogenerated electrons and holes, but also increase the surface area of the catalyst. Both photocatalytic performance and adsorptivity of the catalyst have been improved. The ternary photocatalyst exhibited over 93 % removal efficiency of typical herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) under simulated solar light irradiation with good stability and easy recovery, which justifies the photocatalytic system, a promising application for herbicide or other organic pollutant removal from water.     

叠层式TiO2/SnO2复合纳米薄膜制备及其光电性能研究

采用溶胶-凝胶法在不同基体表面制备了叠层式TiO2/SnO2复合纳米薄膜.用扫描电子显微镜(SEM)、X射线衍射(XRD)对复合薄膜表面形貌和晶体结构进行表征.采用紫外-可见吸收光谱法和电化学方法来研究复合薄膜光学与光电化学性能特征.结果表明,所制备的叠层式TiO2/SnO2复合纳米薄膜表面连续、均匀、致密;XRD分析表明纳米TiO2为锐钛矿型结构,SnO2为金红石型结构;紫外-可见吸收光谱测试表明叠层式TiO2/SnO2复合纳米薄膜较纯TiO2薄膜的吸收范围拓宽;稳定电位随时间变化曲线(OCP-t)结果表明,叠层式TiO2/SnO2复合纳米薄膜光照下其光电化学性能高于纯TiO2薄膜;同时,光照后叠层式TiO2/SnO2复合纳米薄膜能有效储存TiO2先生电荷,延续对不锈钢基体的光生阴极保护性能.经比较,叠加3层SnO2的TiO2/3SnO2复合纳米薄膜改善光电性能最佳.     

Nitrogen-doped TiO2 nanotube array films with enhanced photocatalytic activity under various light sources

Highly ordered nitrogen-doped titanium dioxide (N-doped TiO(2)) nanotube array films with enhanced photocatalytic activity were fabricated by electrochemical anodization, followed by a wet immersion and annealing post-treatment. The morphology, structure and composition of the N-doped TiO(2) nanotube array films were investigated by FESEM, XPS, UV-vis and XRD. The effect of annealing temperature on the morphology, structures, photoelectrochemical property and photo-absorption of the N-doped TiO(2) nanotube array films was investigated. Liquid chromatography and mass spectrometry were applied to the analysis of the intermediates coming from the photocatalytic degradation of MO. The experimental results showed that there were four primary intermediates existing in the photocatalytic reaction. Compared with the pure TiO(2) nanotube array film, the N-doped TiO(2) nanotubes exhibited higher photocatalytic activity in degradating methyl orange into non-toxic inorganic products under both UV and simulated sunlight irradiation.     

柔性染料敏化太阳能电池TiO2薄膜的低温制备技术

简要介绍了柔性染料敏化太阳能电池的特点,综述了柔性染料敏化太阳能电池中TiO2纳米晶半导体薄膜光电极的低温制备技术.     

Electron field emission of a nitrogen-doped TiO(2) nanotube array

A nitrogen-doped titania nanotube array vertically aligned on a titanium substrate exhibits efficient electron field emission. Such a titania nanotube array shows very good stability at high field emission current (fluctuation <3% at field emission current of 160?μA within 4?h) and low turn-on and threshold fields (11.2 and 24.4?V?μm(-1), respectively) because of the coexistence of doped nitrogen and concomitant oxygen vacancies in titania nanotubes. This work demonstrates the possibility of converting pure titania nanotubes without field emission into a favorable and efficient one through the introduction of acceptor states and donor states both above the valence band maximum and below the conduction band minimum in the band gap of titania by the doped nitrogen and concomitant oxygen vacancies, respectively. Application of this doping concept to other transition metal oxides can be expected to broaden the scope of field emission materials.     

直流脉冲阳极氧化制备TiO2纳米管阵列及其特性研究

在乙二醇＋0．5％（质量分数）NH扩的电解质溶液中利用单向直流脉冲电源阳极氧化方法，在电压为40-60v之间制备了直径为90-142nm、管壁厚度为21．8-17nm的TiO2纳米管，SEM测试表明TiO2纳米管的形貌和生长速度密切依赖于氧化处理的电参数，同时通过XRD和Uv-Vis等检测手段对TiO2纳米管退火前后的特性进行了研究。