纳米TiO2／SiO2固相萃取剂的制备及对重金属离子吸附性能的研究

以钛酸四丁酯、正硅酸乙酯作为前驱体,溶胶—凝胶法制备了纳米TiO2／SiO2复合物。采用x射线衍射（XRD）、透射电镜（TEM）、X射线能谱（EDS）等手段对所制得的TiO2／SiO2复合材料进行表征。以纳米TiO2／SiO2复合材料作为填料制成固相萃取小柱,对重金属离子Cu^2＋、Cr^3＋、Pb^2＋和Hg^2＋进行吸附,硝酸洗脱后,采用ICP—MS进行检测。考察了吸附剂对不同pH值溶液中金属离子的吸附性能。自制SPE小柱与ICP—Ms联用测定Cu^2＋、Cr^3＋、pb^2＋和Hg^2＋的最低检出限分别为0．031,0．010,0．041,0．025μg／L。     

稀土修饰电极Pt - TiO2/Eu3+/C对CO电氧化的影响

为研究Pt—TiO2／C电极表面吸附稀土铕离子对CO吸附和氧化的影响,用循环伏安法研究了CO在Pt—TiO2／C,Pt-TiO2／Eu^3 ／C电极上的氧化,发现吸附稀土Eu^3 后,电极表面对CO的吸附明显减弱．CO在电极表面的氧化过电位减小,在酸性溶液中CO的起始氧化电位及氧化峰电位分别负移200mV和210mV;中性溶液中氧化峰电位负移380mV．Eu^3 在电极表面的吸附有利于CO在电极表面的氧化．     

两种形貌TiO2薄膜电极的制备及其光电性能的比较研究

制备了微,纳米TiO2晶体及其薄膜电极和多孔TiO2薄膜电极;采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X-射线衍射仪（XRD）表征微,纳米TiO2晶体的结构,采用扫描电子显微镜（SEM）表征两种薄膜电极的结构,通过测量两种薄膜电极的光电流及I-V特性研究其光电性质。结果表明,微,纳米TiO2晶体是金红石型、纳米棒自组装的球型结构,其薄膜电极为三维结构,而多孔TiO2薄膜电极为二维结构,由于微,纳米TiO2晶体薄膜电极具有大的比表面积,有利于光的吸收利用,表现出优异的光电特性,光电流、短路电流、开路电压分别为2．72μA／cm^2、37．52μA/cm^2、0．146V,比多孔TiO2薄膜电极的相应参数分别提高了28．3％、12．8％、23．7％。     

叶绿素敏化纳米晶太阳能电池性能的研究

用叶绿素作为敏化剂,采用溶胶-凝胶与粉末涂敷相结合的方法在FTO上制备TiO2纳米薄膜电极．实验结果表明,叶绿素可使TiO：薄膜电极对可见光敏感．用xe灯作为光源,在光强为72．6mW／cm^2下,电池开路电压为451mV,短路电流为332μA／cm^2,光电转换效率和填充因子分别为0．774％和38．2％．     

改性热塑性聚氨酯耐热性提高的研究

为了提高热塑性聚氨酯弹性体（TPU）的耐热性,采用三聚氰胺改性脲醛树脂包覆纳米TiO2（MUF／TiO2）,并将其加入TPU中制成复合材料MUF／TiO2-TPU．采用FT—IR、WXRD、SEM、DSC、TGA等分别表征了复合材料的化学结构,并测定了其结晶度、热性能和力学性能．研究结果表明：MUF／TiO2的添加,TPU的结晶形态没有大的变化,但晶粒尺寸略有变小;耐热性得到了很大地提高;改性后的TPU断裂伸长率和拉伸强度呈现先增大后减少的趋势．     

流动注射计时电流法检测甲氧氯普胺

基于多壁碳纳米管修饰印刷碳电极对甲氧氯普胺的电催化作用,建立了测定甲氧氯普胺的流动注射计时电流法与印刷碳电极相比,多壁碳纳米管修饰印刷碳电极显著降低了甲氧氯普胺的氧化峰电位,提高了氧化峰电流．测定甲氧氯普胺的线性范围为8．04×10^-5-1．0×10^-3mol／L,检出限为5．0×10^-5mol／L（S/N=3）;1．0×10^-4mol／L的甲氧氯普胺测定的RSD为3．0％（n=9）．方法已成功应用于药片中甲氧氯普胺含量的测定．     

染料敏化纳米晶MgO/TiO2薄膜太阳能电池

染料敏化TiO2薄膜太阳能电池被认为是硅基太阳能电池的潜在替代产品,但其光电转化效率较低.为了提高光电转化效率,采用物理吸附的方法,利用宽禁带半导体MgO对TiO2光阳极进行表面修饰.研究表明:大部分MgO进入到TiO2的表面结构中,复合薄膜形成的表面势垒改变了TiO2的禁带结构,有效的抑制了电池内部复合反应的进行,使电池的光电转化效率提高.MgO与TiO2之间的界面效应,增加了光在薄膜内的传输路径,使电池吸光度、染料吸附量增加.其中光电转化效率同未经修饰的染料敏化TiO2薄膜太阳能电池相比,提高了24.5%.     

聚合物基纳米银复合物修饰电极的电化学性质

为了研究修饰后银电极对卤素离子的电化学响应性质,运用电化学生长法制备了纳米银L／P（AMPS-MMA）复合物修饰银电极,再通过循环伏安法研究修饰银电极的活性,用差分脉冲法研究了修饰银电极对卤素离子的电化学响应。结果表明,制备的修饰银电极表面吸附一层致密的纳米银L／P（AMPS—MMA）复合物颗粒膜,其粒径在150～200nm;基于这样一种表面结构,修饰银银电极比银电极的活性明显增大。在较宽的卤素离子浓度范围内,即10＾-9-2×10＾-5mo／L,还原峰电流与卤素离子浓度的对数具有很好的线性关系。     

对苯二酚在金纳米粒子/碳纳米管修饰玻碳电极上的电化学行为

制备了金纳米粒子/碳纳米管复合膜修饰的玻碳电极(GNP/CNT/GC),研究该电极上对苯二酚的电化学行为。结果表明:复合膜修饰玻碳电极综合了碳纳米管和金纳米粒子的电催化活性,提高了对苯二酚电化学反应的可逆性,增强了电化学信号,与空白玻碳电极相比,氧化电流增加6倍;对苯二酚在GNP/CNT/GC电极上的电化学反应:低浓度(5×10~(-5)mol/L)时对苯二酚的电极反应受扩散过程控制,而高浓度(5×10~(-4)mol/L)时对苯二酚的电极反应受吸附过程控制。此外还研究了碳纳米管用量,复合膜的层数,扫速等条件对电化学响应信号的影响。     

TiO2光电导测量简介

扼要介绍TiO2的能带结构、表面吸附态以及几种测定TiO2表面光电导的方法，为进一步研究TiO2表面载流子的行为，揭示表面吸附物种在光催化反应中所起的作用和机理提供方法上的参考．     

Kinetics analysis of Ni-TiO_2 composite system during initial stages of electro-crystallization

The initial stage of Ni-TiO_2 composite system electrodeposition on glassy carbon electrode from an acidic solution of nickel sulfate was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Analysis of current density-time transients was performed using the nonlinear fitting procedure and electrochemical impedance spectroscopy was simulated by Z-view software. Besides, the surface morphology of Ni-TiO_2 co-deposition at the initial stage was observed by scanning electron microscopy (SEM). The results show that, in the case of low overpotential (-790 mV vs SCE), the presence of TiO_2 particles in the plating bath makes the nucleation relaxation time tmax decreased clearly. Meanwhile, the electro-crystallization of Ni-TiO_2 system follows a Scharifker-Hills (SH) progressive nucleation/growth mechanism. While in the case of higher overpotential, the presence of the TiO_2 particles in solution makes the nucleation relaxation time tmax increased. At -850 mV (vs SCE), the co-deposition of Ni-TiO_2 system meets SH instantaneous nucleation/growth mechanism. The results of impedance spectra show that the appearance of the characteristic inductive loops represents the nucleation/growth of nickel and the presence of TiO_2 particles reduces the charge transfer resistance of solution. The SEM observation confirms that TiO_2 particles can be considered as favorable sites for nickel nucleating.     

Optimizing electrophoretic deposition conditions for enhancement in electrical conductivity of carbon fiber/carbon nanotube/epoxy hybrid composites

The effectiveness of optimizing electrical conductivity of carbon fiber/carbon nanotube (CNT)/epoxy hybrid composites via Taguchi method was demonstrated.CNTs were induced on carbon fabric by electrophoretic deposition (EPD) technique.The essential deposition parameters were identified as 1) the deposition time,2) the deposition voltage,3) the mass fraction of CNTs in suspension,and 4) the distance between the electrodes.An experimental design was then performed to establish the appropriate levels for each factor.An orthogonal array of L9 (34) was designed to conduct the experiments.Electrical conductivity results were collected as the response.The relative influences of design parameters on the response were discussed.Using the model,signal to noise (S/N) ratio and response characteristics for the optimized deposition parameter combination were predicted.The results show clearly that the optimum condition of electrophoretic deposition (EPD) process improves the electrical conductivity of carbon/epoxy hybrid composites.     

基于多壁碳纳米管修饰的葡萄糖生物传感器

用循环伏安法在玻碳电极表面电沉积了一层稳定的甲苯胺蓝聚合物膜,以此作为电子传递介体,结合多壁碳纳米管、壳聚糖（CHIT）、葡萄糖氧化酶（GOD）混合包埋制备出一种新型葡萄糖生物传感器,实验结果显示,用此法制备的传感器对葡萄特的线性响应范周为5．0×10^-6～2．0×10^-2mol／L,线性相关系数为0．9969。检测限为1×10^-6,响应时间为3．2S,并具有抗尿酸、抗坏血酸等干扰的特点。     

磁性纳米Fe_3O_4颗粒掺杂多壁碳纳米管修饰的葡萄糖生物传感器

磁性纳米Fe3O4颗粒掺杂多壁纳米碳管混合分散于壳聚糖中,得到壳聚糖胶质液.将其修饰到玻碳电极表面,通过交联剂戊二醛固定葡萄糖氧化酶,制得一种新型的传感器.该传感器在pH=6.8的磷酸盐缓冲溶液中,对葡萄糖的线性响应范围为1.0×10^-5-2.3×10^-2mol/L,响应时间5.3 s.     

碳纳米管受介电泳作用三维运动仿真

利用溶于介电液中的碳纳米管在外加交变电场作用下极化产生介电泳力和液体粘滞阻力的共同作用,建立了碳纳米管受力和运动模型;对碳纳米管的运动过程进行了仿真,得到了碳纳米管从特定初始点开始的三维运动轨迹和可以实现组装的碳纳米管初始点分布区域.计算了碳纳米管运动过程中所受介电泳力和速度的变化规律,距离电极间隙越近,碳纳米管受力和速度越大,最大分别能达到10^-9 N和10⁵μm/s的数量级.仿真结果为碳纳米管介电电泳组装提供指导.     

Improvement of luminescent stability from carbon nanotube field emission display based on printed CNT film

Recently, as the applications of carbon nanotubes (CNTs) in field emission display (FED) are broadly and deeply studied [1-7], the luminescence stability of CNT-FEDs have become more and more important. Generally speaking, the impact factors on the lumi- nescent stability include surface reactions between CNTs and gas molecule [8] and the damage at the nanotubes [9] or the CNT-substrate interface [10] caused by resistive heating from high-current field emission. Since the screen printin…     

Growth of graphite film over the tops of vertical carbon nanotubes using Ni/Ti/Si substrate

A substrate with Ni/Ti/Si structure was used to grow vertical carbon nanotubes (CNTs) with a graphite film over CNT tops by thermal chemical vapor deposition with CH4 gas as carbon source.The carbon nanotubes and the substrate were character-ized by a field emission scanning electron microscope for the morphologies,a transmission electron microscope for the microstruc-tures,a Raman spectrograph for the crystallinity,and an Auger electron spectrometer for the depth distribution of elements.The re-sult shows that when the thickness ratio of Ni layer to Ti layer in substrate is about i,a graphite film with relatively good quality canbe formed on the CNT tops.     

毛柄金钱菌碳材料修饰电极测定过氧化氢

以毛柄金钱菌为碳前驱体制备了一种生物质多孔碳材料(BPC), 并将其修饰到玻碳电极(GCE)表面,以此构筑了一种电化学传感器(BPC/GCE).采用扫描电镜(SEM)、 X射线粉末衍射(XRD)、 X射线光电子能谱(XPS)、 拉曼(Raman)光谱和氮气吸附 - 脱附测试对BPC的形貌和结构进行了表征.运用循环伏安法(CV)、 交流阻抗法(EIS)及电流 - 时间曲线研究了过氧化氢(H₂O₂)在该传感器上的电化学行为.结果显示,基于BPC/GCE电极的H₂O₂传感器在15～300 μmol/L范围内, H₂O₂的浓度与传感器信号呈线性关系,检出限为 7.5 μmol/L,且抗干扰能力强.利用所制备的H₂O₂传感器检测人尿中的H₂O₂显示,其加标回收率为95.9%～101.2%,相对标准偏差为2.8%～8.7%,因此该方法可用于人体液中H₂O₂的检测.     

Platinum wire implants coated with PEDOT/carbon nanotube conducting polymer films in the brain of rats: A histological evaluation

Platinum (Pt) implants coated with poly (3, 4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) composite films were implanted into the brain of rats, and the brain response was evaluated 6 weeks after the implantation. The surface morphology of Pt implants with and without the PEDOT/CNT coating was studied using scanning electron microscopy (SEM). After 6 weeks post-implantation, the expression of laminin (vascular endothelial marker) and neuronal nuclei (NeuN, neuronal marker) were evaluated by immnohistochemistry. It is revealed that the obvious improvements of the surface density of blood vessels and neurons aound the Pt implants with the coating, which were evidenced by laminin and NeuN staining in the zone within the distance of 150 μm to the implant interface. These results suggest the PEDOT/CNT composite films can improve the biocompatibility of the Pt electrodes while it is implanted in brain.     

TiO_2气敏元件的空燃比敏感特性

通过气氛模拟实验,研究了TiO_2气敏元件的空燃比(A/F)敏感特性;借助气体边界层模型分析了临界值(A/F)_c的偏移现象。测定了气孔率、催化剂等对气敏速度的影响。采用EPMA技术,分析了元件表面污染状态对其使用寿命的影响。并初步探讨了掺杂对TiO_2电性能的影响以及TiO_2的自身催化氧化过程。