Preparation of TEMPO-contained pyrrole copolymer by in situ electrochemical polymerization and its electrochemical performances as cathode of lithium ion batteries

Composite electrodes based on the nitroxide free radical-contained pyrrole copolymer (PPy-co-PPy-C-TEMPO) as active material were one-step synthesized by in situ electrochemical polymerization, which was then directly applied as the cathode of lithium ion batteries. The structure, morphology, electrochemical property, and charge-discharge performances of prepared copolymers were characterized by FTIR, SEM, cyclic voltammogram, electrochemical impedance spectroscopy, and galvanostatic charge-discharge testing, respectively. The results demonstrated that PPy-co-PPy-C-TEMPO-based composite cathodes have been successfully prepared by in situ electrochemical method, and the introduction of the nitroxide free radical (TEMPO) could obviously affect the morphology and electrochemical characteristics of the obtained electroactive polymers. And the charge/discharge tests showed that with the introduction of the TEMPO, PPy-co-PPy-C-TEMPO-based composite cathodes exhibited an improved specific capacity of 70.9 mAh g^?1 for PPy-co-PPy-C-TEMPO (4:1) and 62.6 mAh g^?1 for PPy-co-PPy-C-TEMPO (8:1) as measured at 20 mA g^?1 between 2.5 and 4.2 V, which were remarkably higher than that of the pure PPy cathode of 41.0 mAh g^?1 under the same experimental conditions. Also, the obtained PPy-co-PPy-C-TEMPO copolymers demonstrated an acceptable cycling stability during the charge-discharge process. These obtained cell performances for the composite cathodes were attributed to the application of the in situ electrochemical polymerization technology, which enhanced the intimate integration between conductive polymer film and electrode. Furthermore, the introduction of TEMPO-contained pyrrole (Py-C-TEMPO) improved the morphology of the composite cathode, which was in favor of the utilization of active materials and the improved electrochemical performances.     

Effects of silver nanoparticle on electrochemical performances of poly(o-phenylenediamine)/Ag hybrid composite as anode of lithium-ion batteries

Journal of Solid State Electrochemistry - In the present work, the poly(o-phenylenediamine)/Ag (PoPD/Ag) hybrid composite with the microrod morphology was prepared by in situ chemical oxidation...     

Sensitive Biosensors Based on (Dendrimer Encapsulated Pt Nanoparticles)/Enzyme Multilayers

A sensitive enzymed‐based biosensor for glucose has been obtained by introducing dendrimer encapsulated Pt nanoparticles via a layer‐by‐layer assembling method. The free amine groups located on each poly(amidoamine) dendrimer molecule were exploited to covalently attach enzyme to the dendrimer chains using carbodiimide coupling. The resultant enzyme electrodes are shown to have excellent sensitivity (as high as 30.33 μA mM^?1 cm^?2) and a limit of detection (about 0.1 μmol L^?1), depending on metal nanoparticles within dendrimers and the biocompatibility of dendrimers, the linear response range to glucose (from 5 μM to 1.0 mM), a fast response time (within 5 s), and good reproducibility (<8% relative standard deviation between electrodes at low substrate concentration). The sensitivities, and stabilities determined experimentally have demonstrated the potential of dendrimer encapsulated Pt nanoparticles as a novel candidate for enzymatic glucose biosensors.     

2-(取代哌嗪-1-甲基)-3-喹啉甲酸乙酯及其衍生物的合成、 表征及晶体结构

以邻硝基苯甲醛为起始原料, 经还原、Friedländer 缩合反应合成2-甲基-3-喹啉甲酸乙酯(2), 2经N-溴代丁二酰亚胺(NBS)溴代得到化合物3, 3再与N-取代哌嗪5a～5p 发生SN2亲核取代反应, 合成一系列2-(取代哌嗪-1-甲基)-3-喹啉甲酸乙酯及其衍生物6a～6p. 它们的结构通过元素分析, IR, 1H NMR, 13C NMR和MS进行了鉴定和表征, 并用X射线衍射法测定了化合物6n的晶体结构.     

Amperometric glutamate biosensor based on self-assembling glutamate dehydrogenase and dendrimer-encapsulated platinum nanoparticles onto carbon nanotubes

A novel amperometric biosensor based on self-assembling glutamate dehydrogenase (GLDH) and poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-PAMAM) onto multiwall carbon nanotubes (CNTs) has been developed for the determination of glutamate. The formation of the self-assembled (GLDH/Pt-PAMAM)_n/CNTs construction was investigated by ζ-potential and high resolution transmission electron microscopy (HRTEM). The results indicated the uniform growth of the layer-by-layer nanostructures onto carboxyl-functionalized CNTs. The electrocatalytic property of the (GLDH/Pt-PAMAM)_n/CNTs modified electrode to glutamate in presence of NAD⁺ (β-nicotinamide adenine dinucleotide, 0.1 mM) was investigated at a low overpotential 0.2 V by electrochemical measurements. The results showed it had series of attractive characteristics, such as a large determination range (0.2-250 μM), a short response time (within 3 s), a high sensitivity (433 μA/mM⁻¹ cm²) and good stability (85% remains after 4 weeks).     

Laccase behavior in the microenvironment of water core within a biosurfactant‐based reversed micelles system rhamnolipid/n‐hexanol/isooctane/water

Compared with synthetic surfactants (cetyltrimethyl ammonium bromide, sodium bis(2‐ethylhexyl) sulfosuccinate and Tween‐80), the properties of the aqueous core as well as the microenvironment behavior were investigated in water‐in‐oil microemulsions, which are formed by water and biosurfactant rhamnolipid (RL) in the solvent of isooctane/n‐hexanol (1:1, v/v). Besides, as a typical substrate of lignocellulose, guaiacol was used to detect the laccase activity in reversed micelles (RMs). The results were eventually confirmed that RL‐based RM system has higher solubilization ability, more friendly environmental compatibility and milder reaction microenvironment than the others. In this study, triangle phase diagram of surfactant/n‐hexanol/isooctane/water was constructed to analyze the variation of phase behavior between each RM system. For the RL‐based RM system, the effect of the molar ratio of water to surfactant (ω₀) on enzyme hydrolytic activity was also determined to be shown as a bell‐shaped curve and presented a maximum at ω₀ = 19; the O―H stretching vibrations of water in aqueous core was also studied by analyzing the IR spectrum over the region of 3050–3750 cm ^{? 1}. Moreover, kinetic studies showed that the catalytic efficiency of the laccase in RL‐based RM system was lower than in aqueous solution. Nevertheless, the RM system obtained the highest hydrolysis rate at RL concentration of 1.0CMC, which is 0.055 mM. Copyright © 2015 John Wiley & Sons, Ltd.     

Friedl(a)nder反应合成新型喹啉衍生物及其结构表征

以取代和未取代的邻氨基苯甲醛与6-氟-4-色满酮为原料, 在碱性的醇溶液中发生Friedl(a)nder 缩合反应, 除了得到预期的 2-氟-6H-色满并[4,3-b]喹啉及其衍生物2a～2d 外, 还发现这类化合物在碱性溶液中会进一步发生亲核取代反应, 生成2-(3-乙氧甲基)喹啉基-4-氟苯酚及其衍生物3a～3d, 它们的结构通过元素分析, IR, 1H NMR和MS进行了鉴定和表征, 并用X射线衍射法测定了化合物3d的晶体结构.     

Biosensor Based on Self‐Assembling Glucose Oxidase and Dendrimer‐Encapsulated Pt Nanoparticles on Carbon Nanotubes for Glucose Detection

A novel amperometric glucose biosensor based on layer‐by‐layer (LbL) electrostatic adsorption of glucose oxidase (GOx) and dendrimer‐encapsulated Pt nanoparticles (Pt‐DENs) on multiwalled carbon nanotubes (CNTs) was described. Anionic GOx was immobilized on the negatively charged CNTs surface by alternatively assembling a cationic Pt‐DENs layer and an anionic GOx layer. Transmission electron microscopy images and ζ‐potentials proved the formation of layer‐by‐layer nanostructures on carboxyl‐functionalized CNTs. LbL technique provided a favorable microenvironment to keep the bioactivity of GOx and prevent enzyme molecule leakage. The excellent electrocatalytic activity of CNTs and Pt‐DENs toward H₂O₂ and special three‐dimensional structure of the enzyme electrode resulted in good characteristics such as a low detection limit of 2.5 μM, a wide linear range of 5 μM–0.65 mM, a short response time (within 5 s), and high sensitivity (30.64 μA mM^?1 cm^?2) and stability (80% remains after 30 days).     

Corrosion and electrochemical behavior of water glass coatings embedded with graphite/titanium oxide on 2A12 aluminum alloy

Journal of Solid State Electrochemistry - Graphite/titanium oxide composite anti-corrosion coatings with five proportions of graphite were applied on the surface of aluminum alloy. The surface...     

Photo-Response with Radical Afterglow by Regulation of Spin Populations and Hole-Electron Distributions

No matter photoinduced organic radicals have been reported frequently, they are usually non-luminescent at ambient conditions. The internal mechanism on stability and electronic transitions of photoinduced radicals, is thus crucial for the development of relevant materials. Herein, a series of photoinduced radical emission systems were developed conveniently through doping benzoic acids into the hydrogen donor polyvinyl alcohol (PVA) matrix. Visual photoinduced radical emission and photochromism could be observed on Ph-3COOH @PVA film with the formation of cyclohexadienyl-type structure. For the first time, radical afterglow appeared with energy transfer from triplet state. The appropriate introduction of carboxylic groups to three nonadjacent carbon atoms on the benzene ring was the best for decreasing spin population and promoting electronic transitions of the radical. This study largely expands the radical emission property from both internal mechanism and practical application.