载铂TiO2纳米管的制备与表征

对在TiO₂纳米管表面上沉积铂进行了研究.HRTEM、XPS结果表明:第一步沉积在粉末TiO₂表面上的铂粒为纳米尺寸,系由PtO₂和Pt(OH)₂组成;第二步制成纳米管后,铂粒在纳米管外表面分布均匀.为下一步以TiO₂纳米管作为催化剂载体的研究奠定了基础.     

电沉积Cu对纳米结构Ti-16Zr合金腐蚀性能的影响

采用阳极氧化法在Ti-16Zr合金表面上制备TiO2纳米管,然后通过恒电位电沉积法在TiO2纳米管上沉积Cu,获得Cu/TiO2,并分析基体Ti-16Zr合金、TiO2纳米管以及Cu/TiO2在人工模拟体液中的耐腐蚀性能。结果表明在基体Ti-16Zr合金上形成了整齐有序的TiO2纳米管阵列,平均直径大约为110nm,管壁厚度大约为20nm。在TiO2纳米管上沉积Cu后,其表面被相对均匀且致密的微米大小的球状颗粒覆盖,出现了明显的团聚现象。TiO2纳米管和Cu/TiO2发生了点蚀,而Ti-16Zr发生了均匀腐蚀。试样在人工体液中的耐腐蚀性排序为Ti-16ZrTiO2纳米管Cu/TiO2,即基体Ti-16Zr在人工体液中的耐腐蚀性最好。     

载Pt-TiO2纳米管阵列制备及其光电催化性能

采用阳极氧化法在纯钛箔表面制备TiO2纳米管,再用直流电沉积法在纳米管内沉积Pt,制备出载Pt-TiO2纳米管电极.并采用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)对其进行表征.研究载Pt-TiO2纳米管阵列与TiO2纳米管阵列对有机磷农药敌敌畏(DDVP)的光电催化降解效果,并与光催化、电降解做了简单对比.结果表明:所制Pt-TiO2纳米管存在锐钛矿晶型TiO2,其饱合光电流比TiO2纳米管大.与单独光催化、电降解相比,载Pt-TiO2纳米管电极光电催化降解效果更显著.     

阳极氧化法制备TiO2纳米管阵列及其光电性能研究

采用阳极氧化法在钛片上制备了TiO2纳米管阵列光电极，利用扫描电子显微镜（SEM）和X射线衍射仪（xRD）对TiO2纳米管的形貌和结构进行了表征，详细考察了氧化工艺参数对纳米管阵列形貌的影响，并通过稳态光电响应技术对TiO2纳米管电极的光电化学性能进行了研究．结果表明，在1wt％HF电解液中，控制氧化电压为20V，反应30min后，在Ti表面获得了垂直导向的TiO2纳米管阵列，孔径约为90nm，管壁厚度约为10nm．经600℃退火处理后，TiO2纳米管阵列为锐钛矿型与金红石型的混晶结构，此时电极的光电性能最佳，与TiO2纳米多孔膜电极相比，光电性能大幅提高．     

CeO2修饰的透明TiO2纳米管电极的电致变色器件

采用电化学沉积法在阳极氧化制备的TiO2纳米管阵列管壁上沉积一层CeO2纳米颗粒,再将CeO2修饰的透明TiO2纳米管阵列薄膜对电极与聚三甲基噻吩变色电极组装成透过型电致变色器件.实验结果表明:CeO2修饰的TiO2纳米管阵列薄膜仍保持良好的光透过性,其电荷存储能力比纯TiO2纳米管电极提高了30%.经CeO2修饰的TiO2纳米管改善了器件的性能,与对电极为单一TiO2纳米管阵列的器件相比,其对比度仍保持在38%左右,其褪色时间由1.3 s缩短为0.8 s.电致变色器件快速响应得益于纳米管与纳米颗粒组成的复合结构的高比表面积和快速的电荷传输过程.     

二氧化钛有序纳米阵列染料敏化太阳能电池光阳极的研究进展

介绍了染料敏化太阳能电池(DSSC)的结构和基本原理,综述了近年来作为DSSC光阳极的TiO2纳米管、纳米线、纳米棒阵列的制备工艺进展,重点介绍了阳极氧化法制备纳米管和水热法制备纳米线和纳米棒.阐述了通过改进TiO2纳米管提高DSSC效率的几种途径,包括优化纳米管的尺寸、改善纳米管的输运性能、在透明基板上生长纳米管、对纳米管进行表面修饰等.最后展望了TiO2纳米阵列DSSC的研究方向.     

硅掺杂TiO2纳米管阵列的制备及光电催化活性的研究

通过电化学沉积,在阳极氧化法制备的高度有序TiO2纳米管阵列表面均匀地沉积Si元素.扫描电子显微照片显示Si掺杂的TiO2纳米管垂直于基底定向生长.X射线衍射分析表明,所引入的Si可能掺入到TiO2的晶格中,因而提高了TiO2的热稳定性,抑制了金红石相的生成及晶粒的长大.紫外-可见漫反射分析表明Si掺杂的TiO2纳米管吸收边带发生了明显的蓝移,并且在紫外区的吸收强度明显增强.与未掺杂的TiO2纳米管相比,Si掺杂TiO2纳米管电极的紫外光电化学响应显著提高,其光电流密度是未掺杂的1.48倍.硅掺杂TiO2纳米管阵列光电催化降解五氯酚的动力学常数(1.651h-1)是未掺杂TiO2纳米管电极(0.823h-1)的2.0倍.     

ZnO纳米棒为模板的TiO2纳米管制备及其场发射性能研究

以水热法生长ZnO纳米棒阵列为模板,利用液相沉积法成功制备了TiO2纳米管阵列,并系统研究了液相沉积液浓度和沉积时间对ZnO纳米棒的溶解情况,以及所制备TiO2纳米管阵列的场发射性能。实验结果表明:硼酸浓度越大、沉积时间越长,对ZnO纳米棒的溶解作用越明显,因而越不利于TiO2纳米管的制备。利用该种方法制备的TiO2纳米管长径比和致密性可通过ZnO纳米棒的水热生长条件来控制,本实验制备的TiO2纳米管具有优异的场发射性能,其开启场强为4.60 V/μm,场增强因子为10239。     

掺杂TiO_2纳米管的润湿性能与体外生物活性(英文)

以低模量钛合金(Ti35Nb和Ti35Nb15Zr)为阳极氧化基材,采用表面阳极氧化方法制备出铌元素和锆元素掺杂的非晶TiO2纳米管阵列,比较了掺杂前后纳米管的润湿性能与体外生物活性.实验结果表明,加入铌和锆元素可减小TiO2纳米管的管径,并有助于增大TiO2纳米管的长度.TiO2纳米管表现出与未氧化前的金属基材所不同的疏水行为.掺杂TiO2纳米管的润湿性随着掺杂元素的变化而变化,铌元素的掺杂可使TiO2纳米管的润湿性改善,铌元素和锆元素共同掺杂对润湿性的改善作用更明显.在模拟体液(SBF)中浸泡后,掺杂TiO2纳米管可快速诱导磷灰石的形成.铌锆元素共同掺杂的纳米管在初始浸泡阶段呈现较快的磷灰石沉积速率.上述研究结果表明,可以通过基材合金化设计来调控或修饰材料表面的亲水或疏水性能,从而探索掺杂TiO2纳米管的生物学性能。     

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。     

Pt-TiO2纳米管电极的制备及电催化性能

采用电化学阳极氧化-阴极还原法制备Pt-TiO2纳米管电极.扫描电镜(SEM)结果显示TiO2纳米管平均管径100nm,管长470nm,管壁厚20nm,且其比表面积大,同时纳米Pt微粒分散在TiO2纳米管上,且粒径细小,Pt微粒充分裸露,使得Pt-TiO2纳米管电极活性点多,电催化性能高.对甲醇的电催化性能测试表明:同纯Pt电极和Pt-TiO2电极(Pt微粒固定在TiO2致密膜上)相比,Pt-TiO2纳米管电极对甲醇具有更高的电催化活性,其氧化峰电流密度是在纯Pt片电极上的20倍以上.     

Pt/TiO2-NTs复合材料的制备及其甲醇电氧化机理研究

采用水热法合成锐钛矿型TiO2纳米管(TiO2-NTs),并以其为载体制备了Pt/TiO2-NTs复合材料。用TEM、XRD对复合材料的形貌和结构进行了表征,TEM测试表明Pt纳米粒子以簇状形式均匀地分散在TiO2纳米管表面。运用循环伏安法研究了Pt/TiO2-NTs复合材料在不同条件下对硫酸中甲醇的电催化活性,并讨论了甲醇的电氧化机理。结果表明,Pt/TiO2-NTs复合材料具有出色的电催化活性。因此,TiO2-NTs被认为是非常有潜力的燃料电池贵金属催化剂载体材料。     

Electro-oxidation of methanol on TiO2 nanotube supported platinum electrodes

TiO2 nanotubes have been synthesized using anodic alumina membrane as template. Highly dispersed platinum nanoparticles have been supported on the TiO2 nanotube. The supported system has been characterized by electron microscopy and electrochemical analysis. SEM image shows that the nanotubes are well aligned and the TEM image shows that the Pt particles are uniformly distributed over the TiO2 nanotube support. A homogeneous structure in the composite nanomaterials is indicated by XRD analysis. The electrocatalytic activity of the platinum catalyst supported on TiO2 nanotubes for methanol oxidation is found to be better than that of the standard commercial E-TEK catalyst.     

Pt/Y<Subscript>2</Subscript>O<Subscript>3</Subscript>:Eu<Superscript>3+</Superscript> composite nanotubes: Enhanced photoluminescence and application in dye-sensitized solar cells

Y(OH)3:Eu3+ nanotubes were synthesized using a facile hydrothermal method,and then,Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing.The resulting Pt/Y2O3∶Eu3+ composite nanotubes not only exhibited enhanced red luminescence under 255-or 468-nm excitation but could also be used to improve the efficiency of dyesensitized solar cells,resulting in an efficiency of 8.33％,which represents a significant enhancement of 11.96％ compared with a solar cell without the composite nanotubes.Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dye|I3-/I-electrolyte interface of the TiO2-Pt/Y2O3:Eu3+ composite cell was much smaller than that of a pure TiO2 cell.In addition,the TiO2-Pt/Y2O3:Eu3+ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.     

A simple route to platinum and Pt-based composite nanotubes

Platinum (Pt) and Pt-based composite nanotubes were fabricated by a facile dipping method within alumina templates. The morphology, structure, and composition of the nanotubes were characterized by SEM, TEM, and EDX. A hydrogen sensor based on Pt/TiO2 composite nanotubes showed high hydrogen sensitivity.     

Pt/C doped TiO2/SWNTs as catalyst for methanol oxidation

Platinum/carbon doped titanium dioxide/single-walled carbon nanotubes (Pt/C/TiO2/SWNTs) were successfully prepared by blending method. These composite catalysts were found to exhibit an anatase TiO2 structure with uniform Pt/C and the existence of SWNTs can be confirmed by transmission electron microscopy (TEM). The composite of Pt/C with TiO2/SWNTs could improve an enhancement in catalytic properties upon applying TiO2/SWNTs as catalyst support. The catalytic oxidation of methanol of Pt/C doped TiO2/SWNTs is found to be higher as compared to the undoped and Pt/C doped materials.     

Promotion of generation of hydrogen by splitting of water by CNT over Pt/TiO2 catalysts

The generation of hydrogen over CNT/Pt/TiO2 catalysts by the splitting of water under irradiation with UV light is studied. The maximum rate of evolution of hydrogen was 2300 micromolg(-1)h(-1) on 0.06 wt% Pt/TiO2 (sol-gel) and reached a stable value of approximately 2000 micromolg(-1)h(-1) when the Pt loading exceeded at a Pt loading of over 0.06 wt%. Single wall carbon nanotubes (SWCNTs) were applied to enhance the hydrogen generation activity. The evolution rate of hydrogen on 0.06 wt% Pt/0.02 wt% SWCNT-TiO2 (sol-gel) was 3836 micromolh(-1)g(-1). 0.1 M NaCI yielded more hydrogen than any other tested salt. The XRD spectra show that the crystal lattices of commercial TiO2 (ST-21) and self-made TiO2 (sol-gel method) are of the anatase form. However, the TEM images and other catalytic activity data show that the SWCNTs act as wires for the transmission of electrons.     

Pt负载型二氧化钛纳米管/纳米晶复合光催化剂的制备及其光催化性能

结合强吸附能力与高光催化活性的催化剂有望更有效地除去废水中的污染物. 以Degussa P25二氧化钛为原料, 采用水热法制备了二氧化钛纳米管(简称为TNTs), 将TNTs加入到溶有氯铂酸和柠檬酸(还原剂)的无水乙醇中, 在蒸汽相水解装置中通过一步法制备了Pt负载型二氧化钛纳米管/纳米晶复合光催化剂. 蒸汽相处理过程中, 部分纳米管转变为锐钛矿相TiO₂, 仍有部分以管的形式存在, 使纳米复合物保留了较高的吸附能力. 利用X射线衍射(XRD)、透射电子显微镜(TEM)、比表面及孔隙度分析仪等方法对产物进行了表征. 结果表明, 粒径约为4 nm的金属性Pt较好地分散在TNTs及由纳米管转变而来、晶粒尺寸约为8 nm的锐钛矿相TiO₂晶粒表面, 复合物保留了高于216 m²/g的比表面积. 光催化降解染料酸性红及亚甲基蓝的实验结果表明, 纯管有较好的吸附能力, 但是光催化性能非常低, 经120℃蒸气处理并负载贵金属Pt后光催化活性有了显著的提高.     

Electrocatalytic applications of platinum-decorated TiO<Subscript>2</Subscript> nanotubes prepared by a fully wet-chemical synthesis

Pt-decorated \(\hbox {TiO}_{2}\) nanotubes Pt@TiO₂ are prepared only by applying a set of facile wet-chemical redox reactions to ion track-etched polycarbonate templates. First, a homogeneous layer of Pt nanoparticles is deposited onto the complex template surface by reducing potassium tetrachloroplatinate with absorbed dimethylaminoborane. Second, the template is coated with a conformal \(\hbox {TiO}_{2}\) layer, using a chemical bath deposition reaction based on titanium(III) chloride. After the removal of the template, the rutile-type \(\hbox {TiO}_{2}\) nanotubes remain decorated with Pt nanoparticles and nanoparticle-clusters on their outside. During the process, neither vacuum techniques nor external current sources or addition of heat are employed. The crystallinity, composition, and morphology of the composite nanotubes are analysed by X-ray diffraction, scanning and transmission electron microscopy as well as by energy-dispersive X-ray spectroscopy. Finally, the obtained materials are examplarily applied in the electrooxidation of ethanol and formic acid, and their performances have been evaluated. Compared to conventional carbon black-supported Pt nanoparticles, the Pt@TiO₂ nanotubes show higher reaction rates. Mass activities of 2.36 \(\hbox {A}\hbox { mg}_{\rm Pt}^{-1}\hbox { cm}^{-2}\) are reached in ethanol oxidation and 7.56 \(\hbox {A}\hbox { mg}_{\rm Pt}^{-1}\hbox { cm}^{-2}\) in the formic acid oxidation. The present structures are able to exploit the synergy of Pt and \(\hbox {TiO}_{2}\) with a bifunctional mechanism to result in powerful but easy-to-fabricate catalyst structures. They represent an easily producible type of composite nanostructures which can be applied in various fields such as in catalytics and sensor technology.