可见光响应Pt沉积La2O3/TiO2制备及其对甲苯的光热催化去除

以钛酸四丁酯和硝酸镧为原料,采用溶胶—凝胶法制备La2O3/TiO2,通过光沉积法在La2O3/TiO2表面负载纳米Pt粒子.采用XPS、FTIR、XRD、DRS、TEM和低温氮物理吸附对光催化剂的晶体结构、光谱特征和表面结构进行表征.考察了催化剂在可见光下对甲苯的去除性能和温度对催化剂去除甲苯的影响.结果表明,沉积的Pt以单质和吸附氧的形式存在,其中以吸附氧的形式为主.Pt的掺入没有引起TiO2相结构的变化,减小了晶粒尺寸并增大了催化剂的比表面积.纳米Pt均匀地分布在La2O3/TiO2上,尺寸分布比较均一,大约为5～10nm.Pt-La2O3/TiO2的表面羟基官能团伸缩振动明显增强,比TiO2和La2O3/TiO2具有更高的可见光催化活性.Pt-La2O3/TiO2对甲苯的降解率,随着温度的升高而增大,产生了与光催化作用平行的热催化作用.气相甲苯光热催化过程不是光催化与热催化的简单叠加,而是存在协同作用.     

乙基纤维素/TiO2复合膜的制备及气体渗透性能

以乙基纤维素(EC)和正钛酸丁酯(TBT)为主要原料,通过溶胶-凝胶(Sol-Gel)法制备了EC/TiO2复合膜。研究了TiO2粒子在复合膜中分布形貌、复合膜的结构变化及对气体渗透和分离性能的影响。结果表明,TiO2质量分数达到25%时,微米级的TiO2粒子均匀分散在复合膜中,复合膜形成有机-无机三维网络结构,测试气体在膜中的渗透行为主要受动力学因素控制,其中H2、O2透气系数分别增大至纯EC膜的1.8倍和1.3倍,H2/N2及O2/N2分离性能略有提高。     

CdIn2O4薄膜性质及其应用研究

利用射频反应溅射法在玻璃衬底上在Ar和O2气氛中从Cd-In合金靶上制备出了CdIn2O4薄膜.实验结果表明退火处理对CdIn2O4薄膜的光电性质有重要的影响.退火处理进一步降低了CdIn2O4膜的电阻率,在可见光区域内该膜的最高光透射率超过了90%.研究还发现CdIn2O4膜电阻在CO气氛中十分敏感的发生变化,并且提高温度和在膜上生长不连续的Pt粒子可进一步增强气敏特性.实验研究还表明CdIn2O4膜气敏传感器响应时间比通用的气敏元件快得多.     

电泳沉积法制备Ba0.6Sr0.4TiO3厚膜及其电学性能研究

采用电泳沉积法在Pt/Ti/SiO2/Si基底上制备了厚度为33μm的Ba0.6Sr0.4TiO3(BST40)厚膜,研究了其介电调谐特性、漏电流特性和铁电特性.实验结果表明:采用水热法制备纳米BST40粒子,经250MPa高压压制,950°C热处理后,BST40厚膜可形成完整的立方钙钛矿结构且表面致密、无裂纹. ε-V特性表明,1kHz时厚膜调谐率可达59.2%.Ⅰ-Ⅴ特性表明,当电压从-25～25V变化时,漏导电流100μA/cm2.测量了在1kHz,不同温度下厚膜的电滞回线.在0°C时,其剩余极化强度为1.06μC/cm2.     

纳米TiO2膜的制备及电学性能研究

本文通过采用丝网印刷法制备了以)α－Al2O3基片为衬底的纳米和微米级TiO2厚膜，气敏性测试表明，纳米TiO2膜的电阻略高于微米TiO2膜，在实验温度范围内，电阻随氧分压的变化率明显高于微米膜，同时还以XRD，SEM对膜材料的结构和形貌进行了表征．     

Pt/Fe2O3/TiO2的制备、表征及其光催化活性研究

报道了担载不同贵金属或过渡金属氧化物的TiO2催化剂对空气中微量甲醛的光催化氧化的研究结果.实验发现,TiO2上担载Fe2O3或Pt时对甲醛均有较高的光催化氧化活性.同时担载双组分的光催化剂Pt/Fe2O3/TiO2,由于2种组分的协同作用,具有更高的光催化活性.研究了催化剂制备因素、催化剂的结构及表面特性对催化活性的影响.     

Si2O3粒径对传感器用L-MBE沉积Pt/ZnMgO/Si2O3导电性能和组织的影响北大核心CSCD

为了提高高温下声表面传感器导电稳定性,采用激光分子束外延方(L-MBE)法沉积制备Pt/ZnMgO/Si2O3三层薄膜,通过实验测试的方式研究Si2O3粒径对其导电性能和结构的影响,重点研究了薄膜受到高温作用时发生的导电性变化及其微观组织结构的转变。研究结果表明:不同Si2O3粒径下Pt/ZnMgO/Si2O3三层薄膜电阻表现为和温度相近的变化规律,当温度上升后都发生了缓慢增大。当薄膜表面Si2O3粒径为60μm时,电阻发生明显变化的温度依次为1100℃与1150℃。粒径达到90μm以上的薄膜经过保温后电阻保持基本恒定。对200μm粒径Si2O3膜薄膜进行热处理形成了平整表面,生成了许多小尺寸晶粒。随着Si2O3粒径降低,表面区域产生了更大外径尺寸的Pt颗粒,形成了部分Pt微孔。提高Si2O3粒径后,形成强度较低的Pt(111)衍射峰,以及更大半峰宽。Pt(111)衍射峰峰半高宽随Si2O3粒径增加表现出降低变化。     

改进的Sol-gel法制备Ba0.6 Sr0.4 TiO3厚膜

采用Sol-gel法在Pt/Ti/SiO2/Si和Al2O3基片上制备厚度为2～14μm的Ba0.6Sr0.4TiO3(BST)铁电厚膜材料.经高能球磨细化和表面改性后的BST陶瓷纳米粉体分散到BST溶胶中,通过甩胶法,形成0-3型BST厚膜材料.XRD图谱显示,BST呈现纯钙钛矿相结构;SEM照片显示,BST厚膜均匀致密、无裂纹;介电性能测试结果表明,当测试频率为1kHz,温度为25℃时,介电常数为620,介电损耗为0.6.     

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。     

Cu/ n2TiO 2/ PBO复合纤维的制备

以 PBO纤维为基体 , 采用浸渍涂覆法在 PBO纤维表面包覆纳米 TiO 2膜 , 采用化学镀法将 Cu沉积到纳米 TiO 2膜表面 , 制备了 Cu/ n2 TiO 2/ PBO复合纤维 , 研究了影响纳米 TiO 2沉积速率和 Cu 沉积速率的主要因素。结果表明 , 纳米 TiO 2与偶联剂的浓度配比是影响纳米 TiO 2包膜形成的主要因素 , 当纳米 TiO 2与偶联剂浓度配比为 1∶1. 2时 , 制备的 n2TiO 2/ PBO复合纤维界面结合力较好 , 且纳米 TiO 2包覆层比较均匀。影响化学镀铜- 1 的主要因素有镀液成分、 反应时间和反应温度。在镀液成分的浓度配比为 CuSO 4·5H 2O 12 g ·L 、KNaC 4H 4 - 1 - 1 - 1O 68 g·L 、HCHO 6 mL ·L 和 NaOH 10 g·L , 反应温度 50℃, 镀铜时间 20 min的条件下 , 制备了负载均匀 , 界面结合力较好的 Cu/ n2 TiO 2/ PBO复合纤维。     

非晶态TiO_2薄膜用于HMP45D温湿传感器的Pt100电阻保护层

用Pt100薄膜电阻代替金属铂电阻可提高HMP45D温度传感器的精度和响应速度,但面临稳定性下降的问题。我们采用溶胶-凝胶方法在Pt100薄膜电阻表面生成TiO_2保护膜,研究表明,非晶态TiO_2保护膜具有良好的光催化活性,镀了TiO_2保护膜的Pt100电阻可获得逼近Callendar-Van Dusen方程的电阻-温度特性,其温度系数在使用180天后仍能保持原来的97.79%。因此,非晶态TiO_2保护膜在提高Pt100薄膜电阻工作稳定性和使用耐久性方面具有很高的应用价值。     

Rectifying switching characteristics of Pt/ZnO/Pt structure based resistive memory

40 nm thick amorphous ZnO thin films were deposited by radio frequency magnetron sputtering at room temperature and asymmetric electrical switching characteristics are observed in the macroscopic symmetric Pt/ZnO/Pt structure. The crystal structure was examined by X-ray diffraction (XRD). The chemical bonding states of ZnO resistive switching layer was investigated by X-ray photoelectron spectroscopy (XPS). Keithley 4200 semiconductor characterization system was used to measure the current-voltage (I-V) characteristics of the fabricated devices. The results reveal that a reversible resistive switching behavior between the high resistance state and the low resistance state with rectifying effects can be repeated for more than 100 dc cycles. This asymmetric electrical behavior is thought to be related to the naturally self-formed PtOx between ZnO film and the Pt bottom electrode, which introduces an energy barrier when electrons flow from top electrode towards the bottom electrode. The model of Pt/ZnO/Pt memory cell is expected to be able to alleviate the misreading error in cross-point array for high density integrations.     

Electronic bipolar resistance switching in an anti-serially connected Pt/TiO2/Pt structure for improved reliability

Electronic bipolar resistive switching and its degradation in the Pt/TiO2/Pt structure were studied. The electronic bipolar switching was induced from the asymmetric trap distribution of the structure under its unipolar reset state. The imbalanced migration of oxygen accompanied by electronic switching significantly degrades switching endurance. Instead, the anti-serial connection of Pt/TiO2/Pt cells resulted in substantial improvements in endurance, underscoring the importance of vacancy migration in device reliability. In addition, the independent control of resistance states of the two connected cells provides the freedom to control resistance ratio, switching direction, and reliability.     

FeS2/TiO2复合薄膜光电性能

采用溶液浸渍法在ITO导电玻璃表面的多孔TiO2薄膜上沉积了FeS2薄膜.使用Fe2O3粉末保护裸露在外的ITO导电膜在硫气氛中热处理后,制得了FeS2/TiO2复合薄膜.应用B531/H数显测厚指示表、数字式四探针测试仪、XJCM-8太阳电池测试仪等研究了FeS2/TiO2复合薄膜的厚度、ITO导电玻璃的电阻率以及FeS2/TiO2复合薄膜的光电性能.结果表明：此方法制得的FeS2/TiO2复合薄膜具有良好的光电性能;且ITO导电膜的电阻率变化较小.因而适宜制备色素增感太阳能电池（DSSC）.     

Fabrication and characterization of photoelectrode thin films with different morphologies of TiO2 nanoparticles for dye-sensitized solar cells

This study deals with the fabrication of three different morphologies of TiO2 nanoparticles to fabricate two-layer photoelectrode thin film for dye-sensitized solar cells (DSSC). The four different TiO2 morphologies are titania nanotubes (Tnt), TiO2 nanoparticles (H220), TiO2 nanoparticle (SP) and commercial DP-25 nanoparticles (P-25). To prepare the thin films of the photoelectrodes, the first layer is coated by H220 TiO2 nanoparticles, and the second is coated by 3 kinds of materials optimally proportionally mixed - P25, SP and Tnt. The photoelectric conversion efficiency of DSSCs with photoelectrodes fabricated using H220 reached 6.31%. Finally, the TiO2 nanaomaterials with four different morphologies were used to prepare a two layer photoelectrode with the structure of H220/P25-Tnt-SP which was combined with a Pt counter electrode to assemble DSSCs. These DSSCs had photoelectric conversion efficiencies of as high as 7.47%.     

Fabrication of dye-sensitized solar cells using Nb2O5 blocking layer made by sol-gel method

In this study, nanocrystalline Nb2O5 thin film has been prepared via sol-gel process using niobium ethoxide as a precursor. Sol-gel films using various ratios of H2O/Nb have been prepared on fluorinated tin oxide (FTO) glass substrate, and used as electron-blocking layer of dye-sensitized solar cell (DSSC). The Nb2O5 film as deposited was amorphous, but became crystalline with hexagonal phase after heat treatment at 600 degrees C. With higher H2O/Nb molar ratio, denser and more uniform Nb2O5 film surface was obtained. DSSCs with the structure of FTO/Nb2O5/TiO2/Dye/EL/Pt/FTO have been prepared, and their solar-cell performance was evaluated. By introduction of Nb2O5 sol-gel film between FTO and TiO2 layer in DSSCs, energy conversion efficiency could be improved.     

化学镀Ni-P合金/TiO2复合膜的耐蚀性研究

在改进常规制备方法的基础上，提出化学镀/溶胶-凝胶复合法在碳钢表面制备TiO2复合膜的新技术。用衍射研究了复合膜的组织形态，采用环境扫描电镜（ESEM）表征了复合膜的表观和断面形貌，用极化电阻、阳极极化曲线测量等方法研究TiO2复合膜在0.5mol/L硫酸和0.5mol/L氯化钠溶液中的耐蚀性能。结果表明A3钢表面的TiO2复合膜耐蚀性能优良。     

Pt对TiO_2薄膜的结构及可见光光催化活性的影响

采用溶胶-凝胶法辅之以离子溅射制备了TiO2/Pt/TiO2纳米多层薄膜和TiO2/TiO2薄膜.通过SEM观察表明,TiO2/Pt/TiO2中二氧化钛颗粒的平均尺寸在20～40nm之间,而TiO2/TiO2中颗粒平均尺寸在40～80nm之间.TiO2/Pt/TiO2纳米多层薄膜的总厚度约为160nm.TEM观察及SADP结果证实单质Pt颗粒尺寸在20～40nm之间,二氧化钛为锐钛矿型.与TiO2/TiO2薄膜相比,TiO2/Pt/TiO2的光吸收曲线红移了30nm,与此同时,除本征吸收边(365nm)外,它在可见光波段还出现了一个新的吸收边650nm,对应的带隙为1.91eV,这种现象归因于沉积Pt后TiO2/Pt/TiO2薄膜中存在金属与基体的界面强相互作用(SMSI).在可见光光降解甲基蓝的实验中,扣除甲基蓝自身的分解,TiO2/Pt/TiO2多层纳米复合薄膜2h后的光降解率为18.1%.     

Electrical and structural characterization of plasma polymerized polyaniline/TiO2 heterostructure diode: a comparative study of single and bilayer TiO2 thin film electrode

A heterostructure was fabricated using p-type plasma polymerized polyaniline (PANI) and n-type (single and bilayer) titanium dioxide (TiO2) thin film on FTO glass. The deposition of single and bilayer TiO2 thin film on FTO substrate was achieved through doctor blade followed by dip coating technique before subjected to plasma enhanced polymerization. To fabricate p-n heterostructure, a plasma polymerization of aniline was conducted using RF plasma at 13.5 MHz and at the power of 120 W on the single and bilayer TiO2 thin film electrodes. The morphological, optical and the structural characterizations revealed the formation of p-n heterostructures between PANI and TiO2 thin film. The PANI/bilayer TiO2 heterostructure showed the improved current-voltage (I-V) characteristics due to the substantial deposition of PANI molecules into the bilayer TiO2 thin film which provided good conducting pathway and reduced the degree of excitons recombination. The change of linear I-V behavior of PANI/TiO2 heterostructure to non linear behavior with top Pt contact layer confirmed the formation of Schottky contact at the interfaces of Pt layer and PANI/TiO2 thin film layers.     

石墨/TiO2共混碳薄膜对电极的电学与电化学性能研究

本文将石墨、TiO2纳米晶以及TiO2胶体共混,采用旋涂法制备了碳薄膜对电极,并用于组装染料敏化太阳能电池。采用场发射扫描电子显微镜观察薄膜的表面形貌,采用四探针电阻率测试仪、电化学交流阻抗图谱及太阳能电池综合测试仪对碳对电极的电学、电化学性质以及电池的光电性能分别进行测试;研究了薄膜厚度对碳对电极导电性能与电化学催化性能的影响。结果表明随着厚度增加,碳对电极的方块电阻和界面电荷传输电阻均变小,分别可达到26.6Ω.sp-1和11.8Ω.cm-2,而电池的填充因子及光电转换效率增大。当碳薄膜厚度为19.5μm时,光电转换效率可达到Pt对电极的70%。