Formation of PPy/Ta2O5/Ta structure by electropolymerization

Electropolymerization of pyrrole on tantalum (Ta) electrodes was carried out in buffer solutions (0.04 M phosphoric acid, 0.04 M acetic acid, 0.04 M boric acid and 0.2 M sodium hydroxide) containing 0.1 M sodium ptoluenesulfonate (TsONa) under galvanostatic conditions and it was found that a polypyrrole (PPy) and a tantalum oxide (Ta₂O₅) layer are formed on a Ta electrode by an electrochemical oxidation process. The conditions of this simultaneous formation were studied in respect to current density (i_d), pyrrole concentration ([Py]), pH and the amount of electricity. Under certain conditions ([Py] = 0.25 M, pH = 1.8, i_d = 10–20 mA cm^?2, the amount of electricity = 1 C), 6–8 μm thick PPy films were efficiently formed on homogeneous 30–50 nm thick Ta₂O₅ layers. The PPy film showed a high electrical conductivity (110 s cm^?1), adhered well and covered the Ta₂O₅ layer. The resulting PPy/Ta₂O₅/Ta system is therefore proved to have excellent properties as a capacitor.     

电感耦合等离子体质谱法测定高纯氧化钽中28种痕量杂质元素

建立了用电感耦合等离子体质谱仪(ICP-MS)测定高纯氧化钽中28种痕量杂质元素的方法。讨论了质谱干扰及接口效应,采用标准加入法消除基体效应。各元素的方法检出限为0.001~0.1μg/g,回收率为90%~115%,方法适用于纯度为99.999%的高纯氧化钽中痕量杂质元素的测定。     

Chitosan coated molybdenum sulphide nanosheet incorporated with tantalum oxide nanomaterials for improving cancer photothermal therapy

In recent years, two-dimensional nanomaterials (2D) prominent for site specific photothermal treatment (PTT), which are one of the most interesting strategy due to their maximizing cancer cell killing efficiency without the normal cells. Several robust methods are established for 2D material synthesis and improving the photothermal conversion efficiency (PCE), biocompatibility, and photostability in cancer PTT. Such preferred mechanism like nanomaterial decoration on to their surface would enable access to tunable 2D nanomaterial properties to improve cancer PTT. Here, we first time report a robust route for deposition of tantalum (TaO₂) on to chitosan (CS) coated molybdenum sulphite (MoS₂) nanosheet surface via electrostatic interaction, which assists to improve cancer PTT efficiency. Detailed studies prove that prepared TaO₂-CS-MoS₂ nanomaterial shows lack of toxicity, photostability and PCE was calculated from 26 °C to 47.2 °C under the 808 nm irradiation/5 min. Therefore, the TaO₂ deposition particularly interest to promote the photostability, biocompatibility and PCE of bare MoS₂ nanosheets. Therefore, the possible mechanism is highly expected to improve biological features in cancer PTT.     

Properties of Dendrimer‐Encapsulated Pt Nanoparticles Doped Polypyrrole Composite Films and Their Electrocatalytic Activity for Glucose Oxidation

A type of novel electroanalytical sensing nanobiocomposite material was prepared by electropolymerization of pyrrole containing poly(amidoamine) dendrimers‐encapsulated platinum nanoparticles (Pt‐PAMAM), and glucose oxidase (GOx). The Pt nanoparticles encapsulated in PAMAM are nearly monodisperse with an average diameter of 3 nm, and they provide electrical conductivity. Polypyrrole acts as a polymer backbone to give stable and homogeneous cast thin films, and it also defines the electrical conductivity. Both Polypyrrole and PAMAM can provide a favorable microenvironment to keep the bioactivity of enzymes such as glucose oxidase. The homogeneity of GOx/Pt‐PAMAM‐PPy nanobiocomposite films was characterized by atomic force microscopy (AFM). Amperometric biosensors fabricated with these materials were characterized electrochemically using cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and amperometric measurements in the presence of hydrogen peroxide or glucose. All those show the resultant biosensor sensitivity was strongly enhanced within the nanobiocomposite film. The optimized glucose biosensor displayed a sensitivity of 164 μA mM^?1 cm^?1, a linear range of 0.2 to 600 μM, a detection limit of 10 nM, and a response time of <3 s.     

可快速充放电聚吡咯/碳纳米管复合材料电化学聚合与表征

采用恒电流法制备了具有可快速充放电性能的对甲基苯磺酸根(TOS-)掺杂聚吡咯/功能化单壁碳纳米管(PPy-TOS/F-SWNTs)复合材料,扫描电镜(SEM)结果表明该复合材料呈纳米棒状构成的多孔结构,棒径约为70nm;比表面积(BET)测试分析表明该复合材料有着较高的比表面积(12.64m2.g-1)和大的介孔孔隙率(20-40nm).循环伏安(CV)、电化学阻抗谱(EIS)和恒电流充放电(GC)电化学分析表明该材料具有优异的快速充放电性能,在800mV的电位窗和2.5A.g-1(功率密度为2kW.kg-1)的电流密度下该材料具有211F.g-1的比容量(能量密度为18.7Wh.kg-1),而当充放电电流高达80A.g-1(功率密度为60kW.kg-1)时比容量仍可达141.8F.g-1(能量密度为12.6Wh.kg-1),同时该材料还表现出优异的稳定性,在10A.g-1大电流下经历10000圈循环后容量仍保持95.2%.     

一氧化氮在聚钴-席夫碱修饰电极上的电催化氧化

研究了一种新合成的杂环席夫碱Ｎ,Ｎ’－二乙酰吡啶缩双苯胺在铂电极上的电化学聚合、聚合膜与钴（Ⅱ）的配合反应及聚合物膜的电化学性质。实验结果表明,该席夫碱可在电极表面通过电化学聚合反应形成具有良好的机械、化学和电化学稳定性的聚合物膜,该聚合物膜可与钴离子形成稳定的配合物,这种配合物对和分子一氧化氮的电化学氧化有显著的催化作用。     

Formation of niobium and tantalum ylide complexes

The reactions of tri(bis(ethyl)amino)phosphorus ylide (Et₂N)₃PCH₂ with cyclopentadienyl (Cp) metal (V) tetrachloride CpMCl₄ (M = Nb 1; Ta 3) and pentamethylcycopentadienyl (Cp^∗) metal (V) tetrachloride Cp^∗MCl₄ (M = Nb 2; Ta 4) were investigated. The hexa-coordinate ylide adducts complexes 5 (CpNbCl₄(H₂CP(NEt₂)₃)), 6 (Cp^∗NbCl₄(H₂CP(NEt₂)₃)) and 8 (Cp^∗TaCl₄(H₂CP(NEt₂)₃)) with pseudo-octahedral geometry were structurally analyzed with X-ray diffraction. Compound 4 (Cp^∗TaCl₄) reacted with three molar equivalent of phosphorus ylide to form one ionic complex 9 ([H₃C-P(NEt₂)₃][Cp^∗TaCl₅]) which was also structurally analyzed with X-ray diffraction. The possible formation mechanism of compound 9 has been discussed.     

Immobilization of invertase and glucose oxidase in poly 2-methylbutyl-2-(3-thienyl) acetate/polypyrrole matrices

Immobilization of invertase and glucose oxidase in conducting polypyrrole and copolymers of poly 2-methylbutyl-2-(3-thienyl) acetate with pyrrole were achieved via electrochemical method. Sodium dodecyl sulphate was found to be the most suitable supporting electrolyte. Maximum reaction rate, Michaelis-Menten constant and optimum temperatures were determined for native and immobilized enzymes. Storage and operational stabilities of enzyme electrodes were also investigated.     

Simultaneous determination of dihydroxybenzene isomers utilizing a thiadiazole film electrode

The present study reports a sensitive electro-analytical method for the simultaneous determination of dihydroxybenzene isomers by using a thiadiazole film electrode, which was readily prepared by electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode with cyclic voltammetry. The functionalized electrode has a distinguishable and sensitive response to dihydroxybenzene isomers. Under the optimized conditions, the linear stripping peak currents showed good linear relationships with hydroquinone, catechol and resorcinol at concentration ranges 0.50-120, 0.50-110 and 1.00-110 μmol/L, and the detection limits are 0.1, 0.1 and 0.3 μmol/L, respectively. The proposed method is applicable to the simultaneous determination of dihydroxybenzene isomers in real samples with the relative standard deviations of less than 5.7% and the recovery rates of 95.6%-106%. The constructed electrode is characterized by simple preparation, good selectivity, and high sensitivity advantages.     

Photo switchable pendant furyl and thienyl fulgimides containing polypyrroles

We report the new pendant furyl and thienyl fulgimides photochromic switch bearing polypyrroles. The functionalized pyrrole monomers synthesized and structures are ascertained by NMR and mass spectral techniques. The yield of fulgides and fulgimides are improved by using trifluoroacetic anhydride (TFA) as a dehydrating agent. The photo-switching properties of fulgimides monomers are explained by electronic structures of HOMO–LUMO of the monomers using Gaussian 03 packages. The electro-active polymer films deposited on indium tin oxide (ITO) electrodes are characterized by cyclic voltammetry and atomic force microscopy (AFM). The electrochemically formed thin films undergoes photo-switching between open and closed state of fulgimides moiety. The photo-switching properties of the polymer films have been confirmed by UV/vis spectroscopy. Though the films are photochemically stable, their mechanical stability with respect to adhesion to electrode is found to be sensitive to the solvent and electrode material.     

五氧化二钽纳米柱的水热合成和光催化性能

以聚乙烯醇(PEG)为结构导向剂,利用水热法合成了形貌可控的Ta2O5纳米柱.采用X射线衍射、扫描电镜、透射电镜、漫反射紫外-可见光谱和光致发光光谱对所制备样品进行了表征.考察了结晶时间和Ta2O5/Sr(OH)2摩尔比等合成参数对样品形貌的影响,并在此基础上对Ta2O5纳米粒可能的生长机理进行了推测.结果表明,在PEG和Sr(OH)2存在条件下可以合成形貌可控的Ta2O5纳米柱.研究了紫外光下Ta2O5纳米柱降解罗丹明B的光催化性能,发现Ta2O5的形貌对光催化性能有很大影响, Ta2O5纳米柱的光催化性能与其长度和直径比成线性关系.催化降解反应的表观速率常数最高可达0.156 min–1,且经多次循环使用后,样品仍然保持较高的催化性能.     

EFFECT OF ULTRASONIC WAVE ON THE ELECTROPOLYMERIZATION OF PYRROLE

Electropolymerization of pyrrole under ultrasonic field at 20kHz was performed ina series of aqueous and propylene carbonate (PC) solutions. The ultrasonic wave withmoderate intensity at the power of 44W, which is the power threshold of the ultrasonicgenerator used in this work to produce cavitation effect, enhance the conductivity andtensile strength of the polypyrrole films as prepared. However, too high intensity of theultrasonic wave is harmful to the polymerization.     

AC Electrochemical Copper and Aluminum Oxidation in Sodium Acetate Solutions

Electrochemical copper and aluminum oxidation using alternating current of industrial frequency was carried out in an aqueous sodium acetate solution. Simultaneous oxidation of metals accelerates copper oxidation, but does not significantly influence the aluminium oxidation rate. It results in the preparation of the copper-aluminum oxide system with a high content of copper oxide (up to 70 wt %). High energy consumption due to the voltage loss to overcome the resistance of the oxidation product layer on the electrode surface considerably limits the process and its product application. Furthermore, the chemical aluminum oxidation in alkaline medium of an aqueous sodium acetate solution instead of electrochemical one does not result in the power-saturated, nanosized metal oxide formation. The results obtained do not only underline the new technology of nanomaterial production, but also allow scientists to consider the mechanisms of the metal oxidation AC-process.     

Recent progress in the chemistry of 1,3-diene complexes of niobium and tantalum

This short review describes the preparation, structure and reactivity of 1,3-diene complexes of niobium and tantalum and presents a comparison with the similar diene complexes of metals of Group 2, 3 and 4.     

Amperometric cholesterol biosensors based on the electropolymerization of pyrrole and the electrocatalytic effect of Prussian-Blue layers helped with self-assembled monolayers

Three cholesterol biosensor configurations based on the formation of a layer of Prussian-Blue (PB) on a Pt electrode for the electrocatalytic detection of the H₂O₂ generated during the enzymatic reaction of cholesterol with cholesterol oxidase (ChOx) were constructed. The enzyme was entrapped within a polypyrrole (PPy) layer electropolymerized onto the PB film. The influence of the formation of self-assembled monolayers (SAMs) on the Pt surface on the adherence and stability of the PB layer and the formation of an outer layer of nafion (Nf) as a means of improving selectivity were both studied. A comparative study was made of the analytical properties of the biosensors corresponding to the three configurations named: Pt/PB/PPy-ChOx, Pt/SAM/PB/PPy-ChOx and Pt/SAM/PB/PPy-ChOx/Nf. The sensitivity (from 600 to 8500 nA mM⁻¹ cm⁻²) and selectivity of the developed biosensors permitted the determination of the cholesterol content in reference and synthetic serum samples. The detection limit for the Pt/SAM/PB/PPy-ChOx/Nf biosensor was 8 μM. Formation of the SAM on the electrode surface and covering with a Nf film considerably improved the stability and lifetime of the biosensor based on the catalytic effect of the PB layer (as the PB layer was retained longer on the electrode), and the Nf layer protects the enzyme from the external flowing solutions. Lifetime is up to 25 days of use. The formation of the SAM also has an effect on the charge transfer and the formation of the PB layer.     

Electropolymerized Pyrrole‐Substituted Manganese Phthalocyanine Films for the Electroassisted Biomimetic Catalytic Reduction of Molecular Oxygen

We report for the first time on the electroassisted biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole‐manganese phthalocyanine film. The prepared films and their intervention in the electroassisted catalytic reduction of molecular oxygen were analyzed by cyclic voltammetry and UV‐visible spectrophotometry on optically transparent electrodes. The obtained results demonstrate the probable existence of the key‐steps responsible for the suggested formation of the highly reactive manganese oxo intermediate.     

生物功能电极 III. 葡萄糖氧化酶的电化学固定化研究

利用磷酸盐缓冲溶液中吡咯的电聚合, 将葡萄糖氧化酶(GOD)包埋在聚吡咯(PPy)基质中以构成生物功能电极。讨论了溶液pH和聚合电位对酶固定化的影响, 并用IR和交流阻抗谱对酶膜进行表征。GOD的固定化只有当pH>5.5时才能实现, 由此推测酶是以带负电的粒子嵌入PPy的。交流阻抗谱表明这一电极具有有界多孔电极的特征。探索了酶与电子传递体Fe(CN)_6~(3-)同时固定化的可行性。电化学固定化的GOD保持其生物催化活性, 酶反应表观上遵循Michealis-Menten动力学。     

Fabrication of MnS/GO/PANI nanocomposites on a highly conducting graphite electrode for supercapacitor application

We demonstrate a high surface area of manganese sulfide (MnS) nanoparticles via a simple solution method and investigated its morphology, physicochemical, and electrochemical studies. For the first time, we attempted to exploit the polymerization of aniline without adding HCl, as it is corrosive to the metal sulfide. Instead, the acidic group present on the graphene oxide surface plays a significant role to some extent as an acidic dopant in the polymerization process. This in-situ polymerization results in the uniform coverage of granular PANI on the entire MnS/GO nanocomposite, which enhances the interfacial interactions between PANI and MnS/GO nanoparticles. The introduction of graphene oxide (GO) to pristine MnS improved the specific capacitance, surface area, and average pore size. And incorporating PANI to MnS/GO leads to an increase in the interfacial interaction between the different pore sized nanoparticles giving enhanced specific capacitance. The specific capacitance for MnS/GO/PANI nanocomposite as measured by galvanostatic charge-discharge measurements was found to be 773 F/g at 1 A/g current density, and even at higher current density, it showed a specific capacitance of 484 F/g at 3.8 A/g. The specific capacitance obtained for MnS/GO/PANI nanocomposite from CV shows 822 F/g at 10 mV/s and 315 F/g at 200 mV/s. The combinatorial effects without destroying the metal sulfide nanostructure can provide an alternate route to design, promising electroactive nanocomposites is an ideal choice as a cost-effective, next-generation high-performance supercapacitor application.     

9,10-蒽醌-2-磺酸钠盐掺杂对导电聚吡咯电容性能的促进作用

用恒电位法制成以9,10-蒽醌-2-磺酸钠盐(AQS)为掺杂阴离子的导电聚吡咯(PPy)电化学电容器电极材料,并采用循环伏安(CV)、充放电测试、电化学阻抗(EIS)等方法表征电容性质.结果表明,与高氯酸阴离子(ClO4-)掺杂的PPy相比,PPy/AQS电极材料不仅单位质量电容和电极稳定性得到提高,工作电压范围也得以扩大.在1mol·L-1的氯化钾中,工作电压为-0.6至0.6V,扫描速率为50mV·s-1时其单位质量电容达到491F·g-1,比PPy/ClO4-电极材料提高1.5倍.这是由于AQS自身良好的氧化还原活性和AQS掺杂有利于聚吡咯膜形成疏松多孔的纳米及亚微米颗粒结构而导致的.