有序TiO2纳米管阵列结构的可控生长及其物相研究

分别在HF水溶液、含NH₄F和H₂O的乙二醇有机溶液中对Ti箔进行阳极氧化,得到TiO₂纳米管阵列结构.该结构高度有序、分布均匀、垂直取向,且通过阳极氧化工艺条件(如阳极氧化电压、电解液的选择与配比以及氧化时间等)可实现对其结构参数(如管径、管壁厚度、管密度、管长等)的有效控制.利用XRD研究了TiO₂纳米管阵列的物相结构.结果表明：退火前的TiO₂纳米管阵列为无定形结构;分别在真空和氧气氛中50 关键词： 2纳米管阵列')" href="#">TiO₂纳米管阵列 阳极氧化 可控生长     

纳米TiO2叶片状阵列电极的制备及其在染料敏化太阳电池中电子的输运性能

在低温条件下采用定向刻蚀技术, 对金属Ti片表面用H₂O₂溶液进行刻蚀氧化, 制备了垂直生长的纳米TiO₂叶片状阵列薄膜电极. 通过X射线衍射分析表明, 纳米TiO₂叶片状阵列薄膜经500 ℃下烧结1 h后, 从无定型转变为锐钛矿相. 场发射扫描电子显微镜观察表明: 在80 ℃下的H₂O₂溶液刻蚀氧化, 经1 d制备得到的是Ti片表面垂直生长的叶片状阵列, 其形貌均匀且完整地 关键词： 2')" href="#">纳米TiO₂ 叶片状阵列电极 染料敏化太阳电池 电子传输     

CdS化学修饰TiO2纳米管阵列电极的传质特性分析

通过声电阳极氧化-化学沉积的方法制备CdS修饰的TiO₂纳米管阵列,并对其进行形貌表征及光电性能和传质特性的研究。结果表明;相对于未修饰的TiO₂纳米管列电极,CdS纳米粒子的化学修饰在增强电极对可见光吸收能力的同时,可减小电荷载流子的迁移阻力而有效提高光生电荷的分离和传递速率。在超声场中进行化学沉积,CdS纳米粒子可在TiO₂纳米管壁上均匀沉积,使得传质阻力进一步降低而获得相对最大的光电流和电荷载流子密度(9.29×10¹⁹cm^-3)。     

自供能TiO2纳米管紫外探测器的制备与性能研究

采用液相沉积法在ITO衬底上以ZnO纳米棒阵列为模板合成了TiO₂纳米管阵列,并采用SEM、XRD对样品的形貌、结构等进行表征。在此基础上,以空白ITO导电玻璃为对电极制备了光电化学型紫外探测器,并对其光响应特性进行测试。实验结果表明,制得的TiO₂纳米管轻微弯曲,由单一稳定的锐钛矿相组成。制得的自供能TiO₂纳米管紫外探测器对300~400 nm紫外波段非常敏感而对可见光区无响应。在无外加偏压的条件下,TiO₂纳米管紫外探测器能够对紫外光实现探测,表现出自供能特性并且具有较高的光敏性。循环测试结果表明,制得的自供能TiO₂纳米管紫外探测器能够循环工作且性能稳定,上升时间和下降时间分别为0.33 s和0.38 s。     

锐钛矿相TiO2纳米管的制备及其染料敏化太阳电池

以商用金红石相TiO₂粉末为原料,通过在碱性溶液中150℃水热48h的方法合成TiO₂纳米管.采用SEM,TEM,XRD分析手段对TiO₂纳米管的形貌和结构演变进行了表征.制成的TiO₂纳米管与TritonX-100,乙酰丙酮混合后,通过丝网印刷的方法涂敷到ITO导电玻璃衬底上,并且在450℃下烧结30min后得到可应用于染料敏化太阳电池的多孔光阳极.将此光阳极浸泡于N719染料敏化后,与镀铂对电极组装电池,两者之间灌 关键词： 2纳米管')" href="#">TiO₂纳米管 染料敏化太阳电池 水热法     

高度有序的TiO2纳米管在有机电解液中的制备及碳掺杂TiO2纳米管的性能

"采用电化学阳极氧化法,在含有氟离子的有机电解液中,使纯钛表面形成一层高度有序的TiO2纳米管阵列．通过控制不同的阳极氧化电压和时间,可以得到形貌不同的TiO2纳米管．最长的TiO2纳米管接近60 1m,长径比约为600．TiO2纳米管在不同的温度(450、550和650 ℃)下焙烧2 h,采用SEM、XRD、EDS和UV-Vis分光光度仪对样品进行表征．X射线衍射仪测试结果表明制备的TiO2纳米管是无定型的,当在较高的温度下焙烧时,其结构由无定型转变为锐钛型和金红石型．EDS微量分析表明TiO2纳米管中     

多孔TiO2/Al/SiO2纳米复合结构的紫外光吸收特性研究

在SiO₂玻璃衬底上用脉冲激光沉积(PLD)技术,分别沉积Ti和Ti/Al膜,经电化学阳极氧化成功制备了多孔TiO₂/SiO₂和TiO₂/Al/SiO₂纳米复合结构. 其中TiO₂薄膜上的微孔阵列高度有序,分布均匀. 实验研究了Al过渡层对多孔TiO₂薄膜光吸收特性的影响. 结果表明：无Al过渡层的多孔TiO₂薄膜其紫外吸收峰在27 关键词： 2薄膜')" href="#">多孔TiO₂薄膜 阳极氧化 紫外光吸收     

高度有序TiO2纳米管阵列的制备及其生长机制

采用金属钛片和石墨分别作为阳极和阴极,氢氟酸和醋酸的混合溶液为电解液,通过阳极氧化法制备高度有序的TiO2 纳米管阵列. 经过场发射扫描电子显微镜(FESEM), X-射线电子衍射仪分别对样品的形貌,结构进行了研究. 结果表明,TiO2 纳米管的尺寸,形貌都随着外加电压、反应时间的变化而变化;随着退火温度的提高,TiO2 纳米管的结构逐渐由锐钛矿相向金红石相转变. 另外,我们讨论了TiO2 纳米管阵列形成机制.     

中空TiO2纳米球的制备

报道了一种新的无机模板法合成中空的TiO₂纳米球,该法以TiCl₄为钛源,中空Sb₂S₃微球为模板,利用TiCl₄水解产生的TiO₂沉积在模板的表面,同时产生的HCl消蚀Sb₂S₃,一步制备中空纳米材料。     

双金属粒子在光–氢转换中的作用分析

本文采用两步阳极氧化法在TiO₂纳米环/管阵列表面负载Ag、Cu纳米粒子,与单金属修饰样品对比分析得到双金属对TiO₂光电响应和电极/电解液界面性质的影响。同时,XPS、UV-Vis和U-t测试表明AgCu-TiO₂光阳极金属抗氧化性强、可见光吸收好、光生电子寿命长,光电流密度达0.76 mA·cm^-2,对应产氢速率376μL·h^-1·cm^-2。对AgCu-TiO₂/H₂O、Ag-TiO₂/H₂O和Cu-TiO₂/H₂O体系进行分子动力学模拟计算,双金属体系相对较宽的耗尽层可促进光生电子–空穴分离、转移。最终结合热力学、动力学分析得到双金属修饰TiO₂光阳极的电子传输路径。     

含水量对TiO_2纳米管形貌控制参数的影响

以不同含水量的乙二醇溶液为电解液,采用阳极氧化法制备TiO2纳米管阵列。通过记录反应过程中电导率、粘度及回路电流随时间的变化曲线,研究含水量对电解液粘度、电导率及电流等过程参数的影响,分析了纳米管形貌尺寸与TiO2溶蚀所耗电荷量的关系。粘度初始值和初始电导率均与含水量呈三次关系,相关系数分别为0.992 5和0.977 8。在反应过程中,溶液粘度值有缓慢增加的趋势。由于不同含水量的电解液粘度的不同,H+和OH-数量不同,F-迁移速率不同,电导率-时间曲线及电流-时间曲线具有不同的变化趋势,并对其进行了理论分析。当水体积分数为4%,5%,6%和10%时,纳米管的形貌较为有序并且TiO2纳米管阵列表面的碎片较少,纳米管直径变化范围为50nm至72nm,长度变化范围为0.85~1.90μm。F-腐蚀氧化膜时所消耗电量与TiO2氧化膜被腐蚀掉的体积呈一次函数关系,即腐蚀电量越大,腐蚀掉的体积越大,为制备一定形貌尺寸的纳米管提供了一定的控制方法。     

Influence of anodization parameters on the morphology of TiO2 nanotube arrays

TiO₂ nanotube arrays can be fabricated by electrochemical anodization in organic and inorganic electrolytes. Morphology of these nanotube arrays changes when anodization parameters such as applied voltage, type of electrolyte, time and temperature are varied. Nanotube arrays fabricated by anodization of commercial titanium in electrolytes containing NH₄F solution and either sulfuric or phosphoric acid were studied at room temperature; time of anodization was kept constant. Applied voltage, fluoride ion concentration, and acid concentrations were varied and their influences on TiO₂ nanotubes were investigated. The current density of anodizing was recorded by computer controlled digital multimeter. The surface morphology (top-view) of nanotube arrays were observed by SEM. The nanotube arrays in this study have inner diameters in range of 40-80 nm.     

Synthesis and characterization of highly-ordered barium-strontium titanate nanotube arrays fabricated by sol—gel method

Highly uniformed barium-strontium titanate nanotube arrays were fabricated using a porous anodic aluminum oxide template from a barium-strontium titanate sol--gel solution. Electron microscope results showed that nanotubes with uniform length and diameter were obtained. The diameters and lengths of these nanotubes were dependent on the pore diameter and the thickness of the applied anodic aluminum oxide template. High resolution transmission electron microscopy and the selected-area electron diffraction pattern investigations demonstrated the perovskite structure and the polycrystalline of the fabricated barium-strontium titanate nanotubes. The characterization of the electrical and dielectric properties had also been made. Compared to thin film material, the intrinsic leakage current density is almost the same. Besides, at 30~℃, the dielectric constant and dielectric loss of the fabricated nanotube is 80 and 0.027 at 1~MHz respectively.     

Enhanced self‐ordering of anodic ZrO2 nanotubes in inorganic and organic electrolytes using two‐step anodization

This work reports on the optimized growth of self‐ordered ZrO₂ nanotubes in inorganic water‐based and organic electrolyte systems containing small amounts of fluoride employing a two‐step anodization process. We show how surface pretreatments of the metallic Zr substrate can drastically improve the growth and morphology of the resulting anodic ZrO₂ nanotube arrays. Using two step anodization and employing organic electrolytes, highly regular and ordered nanotubular ZrO₂ oxide layers can be grown to significantly increased tube lengths compared with aqueous electrolytes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Temperature influence on the anodic growth of self-aligned Titanium dioxide nanotube arrays

We report about the ambient conditions and electrolytes influence on the synthesis of self-organized titania nanotube arrays prepared by anodic oxidation. Arrays of randomly disordered Titanium dioxide nanotubes with pores diameter ranging between 60 and 100 nm, wall thickness of 25 up to 40 nm and around 300 nm nanotubes length, can be prepared under HF electrolyte and its mixtures with sulphuric acid at RT anodization.     

Application of ultrasonic wave to clean the surface of the TiO2 nanotubes prepared by the electrochemical anodization

In this study, the TiO₂ nanotubes were fabricated by electrochemical anodization in a NH₄F/Na₂SO₄/PEG400/H₂O electrolyte system. Ultrasonic wave (80 W, 40 kHz) was used to clean the surface of TiO₂ nanotube arrays in the medium of water after the completion of the anodization. Surface morphology (FESEM) and X-ray diffraction spectrum of the nanotubes treated by sonication at 0 min, 9 min, 40 min and 60 min were compared. The experimental results showed that the precipitate on the surface of the nanotube arrays could be removed by the ultrasonic wave. The treating time had an influence on the precipitate removal and 9 min (corresponding to 12 Wh) is the suitable time for surface cleaning of the TiO₂ nanotubes on this experimental condition.     

Ni-doped TiO2 nanotube arrays on shape memory alloy

Self-organized Ni-Ti-O nanotube arrays were fabricated through a direct anodization of NiTi shape memory alloy in glycerol-based electrolyte. The growth of Ni-doped TiO₂ nanotube arrays was mainly affected by anodization voltage and temperature. Higher anodization voltage facilitated the growth of uniform nanotube arrays. Large-area open-ended Ni-Ti-O nanotube arrays could form on the surface of the shape memory alloy under a higher anodization temperature. The oxide nanotubes had a gradually changed composition along the growth direction of the nanotube and presented a thermal stability up to 400 °C. The nanotubular oxide demonstrated a much better hydrophilic behavior than that of the traditional oxide layer grown on NiTi substrate through air oxidization. The successful fabrication of Ni-doped TiO₂ nanotube arrays here makes it feasible to further explore excellent physical and chemical as well as biomedical properties of the nanotube-modified surfaces of the NiTi shape memory alloy.     

Fabrication of titanium oxide nanotube arrays by anodic oxidation

The formation of titanium oxide nanotube arrays on titanium substrates was investigated in HF electrolytes. Under optimized electrolyte and oxidation conditions, well-ordered nanotubes of titania were fabricated. Topologies of the anodized titanium change remarkably along with the changing of applied voltages, electrolyte concentration and oxidation time. Electrochemical determination and scanning electron microscope indicate the nanotubes are formed due to the competition of titania formation and dissolution under the assistance of electric field. A possible growth mechanism has also been presented.