酞菁铜/氧化钛纳米复合薄膜的制备及其光导性能的研究

通过电化学阳极氧化法在Ti片上制备了氧化钛(TiO2)纳米管阵列.用这种高度有序的阵列结构作为模板,利用电泳沉积的方法在模板表面沉积了一种有机半导体材料酞菁铜(CuPc),从而得到了CuPc/TiO2有机/无机纳米复合结构.通过场发射扫描电镜(FESEM),透射电镜(TEM)等手段对这种复合结构的表面形貌及结构进行了表征.能谱数据证实了复合结构中有机物的存在.此外,CuPc薄膜的形貌和结构可以通过改变电泳沉积参数(如沉积时间和电压)进行调控,从而得到相应的纳米晶、纳米线和微米线薄膜.用该复合薄膜作为载流子发生层制备的双层光导体的光导性能测试结果表明,与复合前的氧化钛薄膜相比,该复合薄膜的光敏性有明显的提高.     

钛酸纳米管的制备及 TEM表征

采用水热合成法以金红石型纳米TiO2粉为原料制备钛酸纳米管，考察了搅拌、酸洗及焙烧温度对纳米管的形成和结构的影响，并通过TEM观察了产物的形貌、结构．结果显示：持续搅拌能促进原料粉末的定向生长，有利于形成钛酸纳米片；酸洗是纳米管的形成阶段；300℃是纳米管转变为长棒状晶柱的临界温度．实验表明以优化的水热合成法制得的纳米管形貌均一，长度超过1μm，钛酸纳米管长径比为125：1．     

银改性阳极氧化TiO2纳米管及光催化性能研究

利用电化学阳极氧化法在钛片表面制备了TiO2纳米管,以SEM、XRD对其形貌结构进行表征,采用光还原沉积法在硝酸银溶液中得到了Ag/TiO2纳米管,并研究了改性前后TiO2纳米管对甲基橙溶液的光降解能力.结果表明,最佳氧化电压为25V、氧化时间为20min、煅烧温度为500℃.最佳硝酸银溶液浓度为0.2mol/L,最佳光还原时间为60min,光降解率为99％.沉积Ag颗粒大小在10～20nm间,且改性后的光催化性能有很大提高,30min时降解率达到改性前的两倍.     

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.     

Ce3+掺杂钛酸钡纳米管薄膜的制备与性能

以阳极氧化制备的TiO_2纳米管薄膜为模版,通过水热法制备了Ba_(1-x)Ce_xTiO_3(0≤x≤0.08)纳米管薄膜,研究了Ba_(1-x)Ce_xTiO_3的结构、表面形貌及其电性能。采用X射线衍射仪表征其晶体结构,采用扫描电子显微镜和透射电子显微镜观察其表面及断口形貌,采用宽频介电阻抗谱仪测试其介电性能。结果表明,在较为温和的条件下用水热法成功制备出立方相结构的Ba_(1-x)Ce_xTiO_3纳米管薄膜,纳米管孔径在80~95nm之间;将制备的Ba_(1-x)Ce_xTiO_3经退火后生成多晶的Ba1-xCexTiO3纳米管薄膜,且样品的管外径尺寸在90~100nm之间,管壁的厚度为25~30nm,介电常数在1kHz下最高可达472,介电损耗为0.41。     

钛酸纳米管的AFM和STM研究

使用AFM 和STM研究了钛酸纳米管.得到了纳米管表面的精面结构.在纳米管表面观察到一个约0.8nm高的大台阶,这是由于纳米管的螺旋特性造成的.还观察到表面各处有楞边平行于管轴的小台阶.这些小台阶与钛酸片层上的相同,是Ti-O八面体的连接方式造成.这些结果与先前在TEM研究基础上提出的钛酸纳米管模型相符合.     

电解液组分对阳极氧化法制备TiO_2纳米管的影响

在不同电解液组分中采用阳极氧化法制备了不同结构参数的TiO2纳米管,考察了不同电解液组分对TiO2纳米管形貌和尺寸参数的影响.采用场发射扫描电子显微镜(SEM)和X射线衍射仪(XRD)对纳米管的形貌和结构进行了表征,并分析了电解液组分对纳米管生长的影响机制.结果表明,降低电解液中H+浓度以及减少电解液中H2O的含量可有效提高纳米管的长度.     

阳极氧化TiO_2纳米管阵列的制备及其光电化学特性研究

采用简单的电化学阳极氧化法在金属Ti表面制备了TiO2纳米管阵列薄膜,研究薄膜的表面形貌、晶相结构以及光吸收性质,考察其光电极的光电化学特性,结果表明,所制备的纳米管阵列膜结构高度有序,平均管径约90nm,管长约700nm。经过不同温度热处理后,薄膜结晶性质的重要性得到证实,600℃处理的光电极具有最优的光吸收和光电化学性质,最高光转化效率约1.07%。     

多孔氧化铝模板结合sol-gel旋转涂敷法制备PZT纳米管

利用溶胶-凝胶旋转涂敷法在通孔的多孔阳极氧化铝(PAA)模板中制备了锆钛酸铅(PZT)纳米管,研究了溶胶浓度对样品形貌的影响。利用SEM和TEM观察了纳米管阵列和单根纳米管的形貌,采用XRD和EDS图谱分析了纳米管的相结构和化学元素组成。结果表明合成的PZT纳米管结晶良好,具有钙钛矿结构(属于四方晶系);纳米管具有较高的韧性但表面较粗糙,直径和管壁厚度分别约为75和7nm,直径与原始PAA模板的孔径相吻合。在一定范围内调节PZT溶胶的浓度(0.1～0.4mol/L),均能在PAA模板的孔洞中形成PZT多晶纳米管,且组成PZT纳米管的晶粒随着溶胶浓度的增加而变大。     

无定型态TiO_2纳米管的光致亲水性能研究

采用阳极氧化法在钛片表面制备了无定型态的Ti O2纳米管,并通过扫描电子显微镜(SEM)对其表面形貌进行了表征。采用JGW-360A型接触角测量仪测量蒸馏水在Ti O2纳米管上的接触角,研究了光照时间、管径尺寸、管长等因素对纳米管亲水程度的影响。结果表明:无定型态Ti O2纳米管在25 W紫外光照条件下,具有优异的超亲水性能;管径尺寸对亲水性的影响不大;管长增加幅度越大,亲水性提高越显著。     

镍纳米管阵列的电沉积合成及其磁学性能表征

以氧化铝膜为模板、金属汞为电阴极,采用简单的直流电沉积方法制备出高度有序的镍纳米管阵列。利用扫描电子显微镜、透射电子显微镜、选区电子衍射、能谱仪、X射线粉末衍射和样品振动磁强计对样品进行形貌表征、成分及磁性能分析。结果表明,阵列中的镍纳米管彼此平行,尺寸均匀,纳米管外径为260～360nm;镍纳米管阵列表现出良好的磁各向异性,其易磁化方向垂直于镍纳米管阵列。以金属汞为电阴极是易形成纳米管的关键条件。     

An effective and green H_2O_2/H_2O/O_3 oxidation method for carbon nanotube to reinforce epoxy resin

Facile green oxidation methods are always desired to functionalize carbon nanotubes(CNTs) in the production of advanced CNT/epoxy composites. In the present work, an optimized H_2O_2/H_2O/O_3 oxidation method was developed, and performances of the H_2O_2/H_2O/O_3 oxidized CNT in epoxy matrix were tested and compared with that of the H_2O/O_3 oxidized CNT and the most commonly used concentrated HNO_3 oxidized CNT. The physical and chemical characteristics of the obtained oxidized CNTs were systematically characterized via transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS) and Raman. Mechanical performances of the obtained composites were explored by tensile tests,impact tests, dynamic mechanical analysis(DMA) and fracture toughness tests. It was found that the H_2O_2/H_2O/O_3 oxidized CNT exhibited all-around overwhelming advantages over the concentrated HNO_3 oxidized CNT on reinforcing the epoxy matrix, while the H_2O/O_3 oxidized CNT only improved the material strength. Reinforcing mechanisms for the different methods oxidized CNTs were studied and compared.The optimized H_2O_2/H_2O/O_3 oxidation method makes scaled production possible, avoids environment pollutions, and holds great potentials to replace the most commonly used concentrated HNO3 oxidation method to oxidize CNT during the preparation of the advanced CNT/epoxy composite.     

衬底温度对碳纳米管生长和结构的影响

用CH4、NH3和H2为反应气体,利用等离子体增强热丝化学气相沉积在沉积有Ta缓冲层和Ni催化剂层的Si衬底上制备了准直碳纳米管,并用扫描电子显微镜和透射电子显微镜研究了它们的生长和结构随温度的变化.结果表明生长的准直碳纳米管是竹节型结构,其直径随衬底温度的降低而减小,生长速率随衬底温度的升高有一极值.从催化剂在衬底温度作用下的变化开始,分析了衬底温度对碳纳米管生长和结构的影响.     

高浓KOH水溶液中低温合成六钛酸钾前驱体的研究

以偏钛酸为原料在高浓KOH溶液中常压下低温合成六钛酸钾前驱体,然后经烧结制备六钛酸钾.实验表明,合成条件对前驱体的种类、结晶度和形貌有明显的影响,从而显著地影响了六钛酸钾的形貌和产率.水溶液中合成的二钛酸钾具有较高的反应活性,可以在较低温度下经一次烧结制备出六钛酸钾晶须.     

High-aligned carbon nanotube film with netlike bulges

High-aligned carbon nanotubes film with netlike bulges made of catalyst particles has been synthesized on a silica wafer by pyrolyzing ferrocene/melamine mixtures. The structure and composition of carbon nanotubes are investigated by scanning electron microscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electron energy-loss spectroscopy (EELS). It is found that these nanotubes have uniform outer diameters of about 25 nm and lengths of about 40 μm. High-resolution TEM images show that each carbon nanotube is composed of graphite-like layers arranged in a stacked-cup-like structure. XPS spectrum shows that the crust covering the tops of the aligned carbon nanotube film consists of carbon, iron and ferric oxide. The EELS spectrum shows that these nanotubes are pure-carbon tubes. The formation mechanism of the netlike bulges has been provided.     

Preparation and characterization of aligned carbon nanotube-ruthenium oxide nanocomposites for supercapacitors

A novel type of ruthenium oxide (RuO(2))-modified multi-walled carbon nanotube (MWNT) nanocomposite electrode (RuO(2)/MWNT) for supercapacitors has been prepared. The nanocomposites were formed by depositing Ru by magnetic-sputtering in an Ar/O(2) atmosphere onto MWNTs, which were synthesized on Ta plates by chemical vapor deposition. Cyclic voltammetry, chronopotentiometry, and electrochemical impedance measurements were applied to investigate the performance of the RuO(2)/MWNT nanocomposite electrodes. The capacitance of the MWNT electrodes in 1.0 M H(2)SO(4) is significantly increased from 0.35 to 16.94 mF cm(-2) by modification with RuO(2). The RuO(2) film on the surface of the nanotubes is composed of small crystal grains with tilted bundle-like microstructures, as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results demonstrate a promising route to prepare RuO(2)/MWNT-based double-layer supercapacitors.     

Hydrogen-acetylene gas ratio and catalyst thickness effect on the growth of uniform layer of carbon nanotubes

Effect of catalyst thickness (2, 4, and 6 nm) and acetylene-hydrogen gas ratio (1/4, 2/4, and 3/4) on the synthesis of carbon nanotubes is reported in this article. Synthesized nanotubes are characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and Raman effect. From SEM results, nanotubes growth is less for higher thickness, as at higher thickness catalyst nanoparticles agglomerate which suppress the growth of nanotubes. Raman spectroscopy results reveal that at higher thickness defects density increases. Nanotube of better crystallinity and graphitic outer walls grows for lower acetylene-hydrogen gas ratio and at smaller thickness of catalyst layer. The sheet resistance of carbon nanotube thin film is measured by using Hall effect measurement systems. Smallest sheet resistance among synthesized multi-walled carbon nanotubes sample is obtained for nanotubes grown on 2 nm thick catalyst film and is 0.9 kΩ/square.     

钛氧化物的蒸发特性

试验以Ti2O3、Ti3O5和TiO2作为初始膜料，在ZZS7OO—6／G型真空镀膜机上采用O^2-离子束辅助蒸发制备氧化钛薄膜。用XRD检测方法确定各种膜料和薄膜的相成分，并全面的分析了各种膜料的蒸发特性和薄膜；用分光光度计测量薄膜的透射率，并分析薄膜的光学性能。试验表明，在采用Ti2O3、Ti3O5和TiO2作为蒸发制备氧化钛薄膜时，在钛的氧化物中存在Ti3O5固态同一蒸发相；各种膜料在蒸发时，发生分解，熔池中的物质的成分逐渐转变并晟终完全成同一蒸发相成分。     

Synthesis and characterization of Dy(OH)3 and Dy2O3 nanotubes

Dy(OH)3 nanotubes with high aspect ratios of up to about 50 were synthesized in the presence of poly(ethylene glycol) via a hydrothermal method. Poly(ethylene glycol), as a nonionic surfactant, plays an important role in the formation of morphologies. Subsequent thermal treatment of Dy(OH)3 nanotube precursors at 450 degrees C for 6 h led to Dy2O3 nanotubes, during which the precursor tubular morphology was maintained. Selected-area electron diffraction and high-resolution transmission electron microscopy reveal the single-crystal nature of the Dy(OH)3 and Dy2O3 nanotubes. The morphologies and crystalline structure of the as-obtained products were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, respectively. By this method, we can obtain a mass of products.     

Sol-gel方法制备BiFeO_3/Bi_4Ti_3O_(12)多层薄膜及其电性能

采用溶胶-凝胶方法在FTO/glass底电极上制备了BiFeO3/Bi4Ti3O12和Bi4Ti3O12/BiFeO3多层薄膜。研究了室温下薄膜的结构,铁电性质和介电性质,并将其与纯的BiFeO3薄膜的性质进行了比较。从薄膜的XRD模式中可以观察到共存的BiFeO3相和Bi4Ti3O12相。通过电滞回线测量可以看出,相对于纯的BiFeO3薄膜,BiFeO3/Bi4Ti3O12和Bi4Ti3O12/BiFeO3多层薄膜能够承受更高的测试电场而获得充分极化,从而表现出较强的铁电性,在450kV/cm测试电场下,薄膜的剩余极化强度分别为37μC/cm2和23μC/cm2。