Amperometric Glucose Biosensor Based on Glucose Oxidase Encapsulated in Carbon Nanotube–Titania–Nafion Composite Film on Platinized Glassy Carbon Electrode

A highly sensitive and selective glucose biosensor has been developed based on immobilization of glucose oxidase within mesoporous carbon nanotube–titania–Nafion composite film coated on a platinized glassy carbon electrode. Synergistic electrocatalytic activity of carbon nanotubes and electrodeposited platinum nanoparticles on electrode surface resulted in an efficient reduction of hydrogen peroxide, allowing the sensitive and selective quantitation of glucose by the direct reduction of enzymatically‐liberated hydrogen peroxide at ?0.1 V versus Ag/AgCl (3 M NaCl) without a mediator. The present biosensor responded linearly to glucose in the wide concentration range from 5.0×10^?5 to 5.0×10^?3 M with a good sensitivity of 154 mA M^?1cm^?2. Due to the mesoporous nature of CNT–titania–Nafion composite film, the present biosensor exhibited very fast response time within 2 s. In addition, the present biosensor did not show any interference from large excess of ascorbic acid and uric acid.     

Synthesis, crystal structures, and photochromic properties of 6,6′ or 7,7′ or 6,7′-dimethyl-[2,2′-bi-1H-indene]-3,3′-diethyl-3,3′-dihydroxy-1,1′-diones

New photochromic title compounds 1, 2, and 3 have been prepared starting from 4-methylphthalic anhydride. Compounds 3a and 3b are a pair of enantiomers and were obtained as a racemic mixture (numbered as 3). Compounds 1, 2, and 3 were successfully separated from the isomeric mixture product through fractional crystallization, and their structures are confirmed by X-ray crystallographic analysis. UV-vis absorption and photochromic properties of 1, 2, and 3 have also been investigated. Results reveal that the substituents, even like the simple methyl, on the benzene rings of biindenylidenedione could considerably affect the photochromic property, as well as other properties of this kind of compounds.     

Silver nanoparticles immobilized on thin film composite polyamide membrane: characterization,nanofiltration, antifouling properties

Microbial biofouling is one of the major obstacles for reaching the ultimate goal of realizing a high permeability over a prolonged period of nanofiltration operation. In this study, the hybrid nanocomposite membranes consisting of silver (Ag) nanoparticles with antibiofouling capability on microorganism and polyamide (PA) were prepared by in situ interfacial polymerization and characterized by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The hybrid membranes were shown to possess the dramatic antibiofouling effect on Pseudomonas. In addition, Ag nanocomposite membranes had little influence on the performances of the membrane such as on water flux and salt rejection. SEM analysis results showed that all Pseudomonas were dead on the PA/Ag nanocomposite membrane, indicating the effectiveness of silver nanoparticles. This investigation offers a strong potential for possible use as a new type of antibiofouling membrane. Copyright © 2007 John Wiley & Sons, Ltd.     

N-TiO2/ZnO复合纳米管阵列的掺杂机理及其光催化活性

以ZnO纳米柱阵列为模板, 采用溶胶-凝胶法制备出TiO2/ZnO和N掺杂TiO2/ZnO的复合纳米管阵列. 扫描电镜(SEM)、X射线光电子能谱(XPS)和紫外-可见漫反射吸收光谱(UV-Vis)的结果表明: 两种阵列的纳米管均为六角形结构, 直径约为100 nm, 壁厚约为20 nm; 在N-TiO2/ZnO复合纳米管阵列中, 掺入的N离子主要是以N-Ox、N-C和N-N的形式化学吸附在纳米管表面, 仅有少量的N离子以取代式掺杂的方式占据TiO2晶格O的位置; 表面N物种形成的表面态能级和取代式掺杂导致带隙的窄化, 增强了纳米管阵列的光吸收效率, 促进了光生载流子的分离. 光催化实验结果表明, N离子的掺杂有利于N-TiO2/ZnO复合纳米管阵列光催化活性的提高.     

互通多孔碳/二氧化锰纳米复合材料的原位水热合成及电化学性能

以互通多孔碳（IPC）为载体，水热条件下在碳表面原位反应生成纳米结构的二氧化锰（MnO₂），制备互通多孔碳/二氧化锰纳米（IPC/MnO₂）复合电极材料. 采用扫描电镜（SEM），透射电镜（TEM），X射线衍射（XRD），热重分析（TGA）对其结构进行表征；采用循环伏安法、恒流充放电和交流阻抗对其电化学性能进行研究. 结果表明：生成的MnO₂均匀地负载在碳的表面，形成多层次结构，并且随着温度的升高IPC表面负载的MnO₂由纳米颗粒变为纳米片状结构；MnO₂纳米片具有典型的K-Birnessite 型晶体结构；复合物中MnO₂的含量约为34%（w）. 在100 ℃制备的IPC/MnO₂复合材料在三电极系统中最高比电容达到了411 F·g^-1；随着反应温度的升高,比容量先增长后基本保持不变. 以IPC/MnO₂为正极，活性炭（AC）为负极，1 mol·L^-1 Na₂SO₄溶液为电解液组装成IPC/MnO₂//AC 混合超级电容器，发现IPC/MnO₂电极的电容器其电位窗口从1 V扩展到1.8 V，容量可达86F·g^-1，且表现出良好的电容特性和大电流放电性能.     

S/In_2O_3纳米材料的制备及其在锂硫电池正极材料中的应用

以硝酸铟和蔗糖为原料,依次经水热反应和550℃碳化制得In_2O_3纳米材料(nano-In_2O_3);将硫渗入nanoIn_2O_3得S/In_2O_3,其结构和微观形貌经SEM,TEM和XRD表征。将S/In_2O_3,导电炭黑和聚偏氟乙烯按质量比8∶1∶1制成正极材料(1);将1涂覆于铝箔上,锂片作参比电极,1 mol·L~(-1)LiPF_6的DMF/DOL(V/V=1/1)溶液为电解液,组装成锂硫半电池。采用循环伏安法和恒电流充放电法研究了S/In_2O_3的电化学性能。结果表明:在1.95 V和2.3 V处有两个还原峰,2.5 V处有一个氧化峰。电流密度为335 m A·g~(-1),首次放电比容量为1 357m Ah·g~(-1),库伦效率为82.75%。经80次充放电后,放电比容量为537 m Ah·g~(-1)。     

ICP–AES法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼的含量

建立电感耦合等离子体原子发射光谱(ICP–AES)法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼7种元素含量的方法。试样用盐酸与硝酸混合酸溶液溶解,采用溶解国家标准样品的方法制备校准曲线溶液,确定了元素最佳分析谱线。各元素的含量在其测试范围内与原子发射强度呈良好的线性关系,线性相关系数不小于0.999,7种元素的检出限在0.000 3%~0.003 0%之间。该方法应用于铬镍不锈钢标准样品的测定,测定值与认定值相符,测定值的相对标准偏差在0.12%~1.15%之间(n=8)。应用于铬镍不锈钢样品测定时,加标回收率在90%~110%之间。该方法操作简便、迅速,可满足日常铬镍不锈钢中多元素含量的检测需要。     

N,N’-二苯基-N,N’-二(9,9-二甲基芴-2-基)-9-己基-(4,4’-二胺基苯基)咔唑的合成方法及表征

以2,7-二溴咔唑为原料经过N-烷基化、Suzuki偶联反应、Buchwald-Hartwig偶联反应合成了有机发光二极管(OLED)空穴传输材料N,N’-二苯基-N,N’-二(9,9-二甲基芴-2-基)-9-己基-(4,4’-二胺基苯基)咔唑,利用NMR、IR和熔点等分析方法对产物结构进行了表征,并通过TG、UV-Vis及荧光光谱研究了物质的热稳定性和光学性能。     

(Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ-Ce0.9Gd0.1O2-δ复合阴极的制备及电化学性质

采用EDTA-柠檬酸盐法制备了(Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ(PLNCG),并与Ce0.9Gd0.1O2-δ(CGO)形成复合阴极PLNCG-CGO。XRD和SEM分析结果表明PLNCG与CGO在1 000℃具有较好的化学相容性。电化学阻抗测试结果表明PLNCG-30%CGO复合阴极在700℃的极化电阻为0.092Ω·cm2;过电位为39.3 m V时,电流密度达到113.3 m A·cm-2。氧分压分析表明电极反应的速率控制步骤为电荷转移过程。阳极支撑单电池(Ni-CGO/CGO/PLNCG-30%CGO)在700℃的最大输出功率密度达到569 m W·cm-2,开路电压(OCV)为0.76 V。     

Mn-Al和Cu-Mn-Al复合氧化物催化苯甲醇选择氧化反应

用溶胶-凝胶法制备了不同组成的Mn-Al和Cu-Mn-Al复合氧化物两组催化剂,用于苯甲醇选择氧化反应.用X射线衍射(XRD)、N2物理吸附(BET)、扫描电镜(SEM)、H_2程序升温还原(H_2-TPR)、O_2程序升温脱附(O_2-TPD)和X射线光电子能谱(XPS)技术对催化剂进行了结构表征,考察了催化剂组成对催化活性的影响.结果表明:以甲苯为溶剂,O_2为氧化剂,353 K反应5 h,Mn_2Al和Cu_(0.3)Mn_(0.7)Al_2催化剂上的苯甲醇转化率分别为36.6%和40.9%,苯甲醛选择性均为100%.进一步研究表明:催化剂活性与其H2还原性和O_2吸附性有关,高活性的催化剂吸附氧多,生成的活性氧易参与反应.