Preparation of TiO2-Pt hybrid nanofibers and their application for sensitive hydrazine detection

The TiO2-Pt hybrid nanofibers with an average dia. 72.6 nm were fabricated by electrospinning poly(vinylpyrrolidone)-ethanol solution containing platinum acetate and titanium tetraisopropoxide, followed by calcination in air at 500 °C for 3 h. High resolution TEM showed that Pt nanoparticles with an average diameter of ～2 nm were well dispersed in the anatase TiO2 nanofibers. Compared to pristine TiO2 nanofibers (average dia. 67.7 nm), the incorporation of Pt nanoparticles into TiO2 nanofibers can greatly enhance the oxidation of hydrazine in neutral solution. The amperometric hydrazine sensor, using the as-prepared TiO2-Pt hybrid nanofibers as the electrochemical catalyst, shows a wide linear range (up to 1.03 mM), a good limit of detection (0.142 μM), and a high sensitivity of 44.42 μA mM(-1) cm(-2). In addition, the excellent anti-interference property, free of matrix effect from real water samples and good reproducibility make the developed hydrazine sensor promising for real applications.     

Preparation of ordered TiO2 nanofibers/nanotubes by magnetic field assisted electrospinning and the study of their photocatalytic properties

Ordered-and-oriented TiO₂ nanofibers and nanotubes were prepared by magnetic field-assisted electrospinning, and photocatalytic properties of all samples were analyzed under UV–Vis shine. TiO₂ nanofibers/nanotubes prepared by magnetic field-assisted electrospinning showed better degradation effect on rhodamine B, reduced the band gap, increased the contact area of organic pollutants with the sample and higher photocatalytic activity than TiO₂ nanofibers/nanotubes prepared by classical electrospinning. The product obtained after high temperature annealing was a mixed phase of rutile phase and anatase phase and could be advantageous to the segregate of photogenic electron hole pairs and enhance the high dye absorption capacity; Surface roughness could increase more active sites and accelerate the reaction rate of photocatalytic activity; the addition of magnetic field regulated the morphology of TiO₂, and narrowed the band gap to favor photocatalytic performance. The magnetic field-assisted electrospinning study prepared in this paper was an easy-to-use and versatile method for the preparation of ordered TiO₂ nanomaterials, which could be easily extended to practical applications or other materials for photocatalysis and water cleavage.     

静电纺丝制备镍铁纳米纤维及其析氧性能

高效的析氧反应（OER）催化剂对于高效的能量储存和转换是必不可少的。本文采用静电纺丝法结合一步煅烧成功制备了镍铁合金/铁酸镍复合纳米纤维（NiFe/NiFe₂O₄）,通过调变煅烧气氛、温度、元素比例等条件并结合X射线衍射（XRD）、扫描电镜（SEM）和电化学等测试手段对材料进行了相关表征与分析。其中电化学测试结果显示,该材料对碱性介质（1mol/L KOH）中析氧反应具有较高的电催化活性,最佳样品在电流密度达到10mA/cm²时所需过电位为380mV,并且在计时电位法测试10h后也表现出极佳的稳定性。     

Preparation and characterization of barium titanate nanofibers by electrospinning

PVP–BaTiO₃ composite nanofibers were successfully prepared by electrospinning and pure BaTiO₃ fibers were produced after calcination at 1000 °C. A homogeneous viscous solution of barium acetate + titanium acetate/titanium isopropoxide in poly vinyl pyrrolidone (PVP) was prepared by varying PVP concentration in the range of 8–12%. The above sols were electrospun at 9 kV DC by maintaining tip to collector distance (TCD) of 7 cm. The electrospun fibers were calcined at 1000 °C for 2 h. Thermo gravimetric analysis (TGA) of the fibers indicates the complete decomposition of organics below 700 °C with 45% weight loss. Scanning electron microscopy (SEM) study shows the fibers cylindrical, smooth with diameters in the range of 50–400 nm and the aspect ratio >1000. The average diameter of the fibers increases with the increase in PVP concentration. The calcined BaTiO₃ nanofibers were found to be coarse, brittle and diameter reduced by 12%. FT-IR study confirms the formation of metal oxide bond at higher temperature.     

TiO2 nanoparticles loaded on graphene/carbon composite nanofibers by electrospinning for increased photocatalysis

Graphene/carbon composite nanofibers (CCNFs) with attached TiO₂ nanoparticles (TiO₂–CCNF) were prepared, and their photocatalytic degradation ability under visible light irradiation was assessed. They were characterized using scanning and transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible diffuse spectroscopy. The results suggest that the presence of graphene embedded in the composite fibers prevents TiO₂ particle agglomeration and aids the uniform dispersion of TiO₂ on the fibers. In the photodegradation of methylene blue, a significant increase in the reaction rate was observed with TiO₂–CCNF materials under visible light. This increase is due to the high migration efficiency of photoinduced electrons and the inhibition of charge–carrier recombination due to the electronic interaction between TiO₂ and graphene. The TiO₂–CCNF materials could be used for multiple degradation cycles without a decrease in photocatalytic activity.     

Preparation and characterization of potassium sodium niobate nanofibers by electrospinning

In this work, we describe the electrospinning of (K,Na)NbO₃ fibers and the effect of calcination temperature on the final phase composition. The envisaged application is for the fabrication of ferroelectric sensor hybrid materials. A solution of potassium acetate, sodium methoxide, and niobium ethoxide dissolved in methanol, acetylacetone, and acetic acid was mixed with polyvinylpyrrolidone (PVP) dissolved in methanol, producing a viscous solution for electrospinning. Confirmation that the proposed equation on the average diameter of fibers produced from high viscosity solutions was larger than that of a lower viscosity solution was made. A scanning electron microscopy (SEM) study showed the fibers to be cylindrical, smooth with diameters of around 400 nm and an aspect ratio >1000. The electrospun fibers were calcined from 700°C to 1050°C observing the fiber morphology. With increasing calcining temperature, the grain size increased. The calcined (K,Na)NbO₃ nanofibers were brittle and generally found to display the “necklace effect.”     

静电纺丝技术合成SrMnO_3纳米纤维及结构表征（英文）

以四水乙酸锰和硝酸锶为原料,通过静电纺丝法制备了锰酸锶(SrMnO_3)/聚乙烯吡咯烷酮(PVP)复合纳米纤维,在800℃下处理3 h,得到六方晶形结构的SrMnO_3纳米纤维,考察了PVP浓度对纤维结构的影响,并对纤维的结构与性能进行了表征。结果表明:PVP质量分数为8%时,SrMnO_3/PVP复合纤维表面光滑,均匀性好;热处理温度达700℃时,SrMnO_3/PVP复合纤维中PVP完全分解,原料全部转化为SrMnO_3,所得SrMnO_3纳米纤维直径为150~200 nm的六方晶形结构,且具有良好的纯度。     

静电纺丝制备聚丙烯腈纳米纤维及其预氧化

利用聚丙烯腈／二甲基甲酰胺纺丝溶液由静电纺丝制备了聚丙烯腈纳米纤维,纳米纤维的直径在220～760nm。随着聚合物溶液浓度和纺丝施加电压的升高,纳米纤维的直径变大。采用热分析和热重分析研究了纳米纤维的热性能,还用红外光谱对纳米纤维预氧化过程分子化学结构的变化进行了表征,结果表明,纳米纤维有一个很尖锐的放热峰,是聚丙烯腈均聚物典型的放热峰。随着预氧化温度的升高,纤维的内部分子结构发生了变化,表现在红外光谱上最突出的是C≡N在2243～2241cm^-1峰的降低,以及C—H在1684cm^-1峰的降低。     

Preparation and photoluminescent characterization of poly(phenylene vinylene)/TiO2 nanoparticles composite nanofibers by one‐step electrospinning

A simple electrospinning progress, directly mixing method, was used to produce ultrafine poly(phenylene vinylene)/TiO₂ (PPV/TiO₂) composite nanofibers with diameters ranging from 100 to 300 nm. The effects of different TiO₂ content on diameter, morphology, and structure of composite fibers were analyzed by scanning electron microscopy and transmission electron microscope. The results showed that composite polymer nanofibers with smooth surface were obtained when TiO₂ concentration was below 18 wt %. The surface of the composite nanofibers became rougher with the increase of TiO₂ content. The optical properties of the as‐prepared nanofibers were characterized by photoluminescence spectra and photographs, the results showed an increase in intensity of the high‐energy shoulder (510 nm) when the concentration of nanoparticles increased. X‐ray diffraction measurements showed that the increasing TiO₂ content enhanced the amorphous phase of PPV in composite nanofibers. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

静电纺丝制备聚丙烯腈纳米碳纤维

利用静电纺丝制备连续的聚丙烯腈纳米碳纤维;介绍了静电纺丝的原理、影响静电纺丝的主要因素以及制备纳米碳纤维、纳米活性炭纤维、纳米碳纤维复合材料的方法和原理;分析了静电纺丝产率低,难以得到单向平铺的纤维等问题,影响静电纺丝的参数主要有溶液特性、纺丝工艺参数、纺丝环境参数。由静电纺丝得到纳米聚丙烯腈纤维,然后再经预氧化和碳化制备纳米碳纤维,或把纳米纤维预氧化,经活化、碳化制备纳米活性炭纤维。并指出纳米碳纤维具有巨大的潜在应用空间。     

Preparation of atactic poly(vinyl alcohol)/silver composite nanofibers by electrospinning and their characterization

Poly(vinyl alcohol) (PVA)/silver composite nanofibers were successfully prepared by the electrospinning method. Water‐based colloidal silver in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic–inorganic composite nanofibers. The ratio of silver colloidal solution to PVA played an important role in the formation of the PVA/silver composite nanofibers. We prepared two different atactic PVA/silver nanocomposites with number‐average degrees of polymerization of 1700 and 4000 through electrospinning with various processing parameters, such as initial polymer concentration, amount of silver colloidal solution, applied voltage, and tip‐to‐collector distance. The PVA/silver composite nanofibers were characterized by field emission scanning electron microscopy and transmission electron microscopy (TEM). TEM images showed that silver nanoparticles with an average diameter of 30–50 nm were obtained and were well distributed in the PVA nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

电纺制备苯乙烯甲基丙烯酸共聚物单轴定向纳米纤维

采用无皂乳液法合成了带有羧基的苯乙烯-甲基丙烯酸共聚物,并利用静电纺丝技术,得到了不同形貌的直径约为800nm的纳米纤维。同时通过对传统的平面导体收集装置的改进,得到了大面积、单轴定向的功能纳米纤维。     

电纺法制备锂电池纳米纤维材料的结构及应用

近年来,静电纺丝技术制备锂离子电池材料的研究在国际上相当活跃。介绍了静电纺丝技术制备的锂离子电池纳米纤维材料的结构,以及静电纺丝技术在制备氧化物、碳材料、聚阴离子材料、镍钴锰三元锂离子电池正负极材料和制备锂离子电池隔膜中的应用。静电纺丝这一纳米技术应用于锂离子电池领域,对于提高电池的能量密度、功率密度有着广阔的前景。相信随着研究的不断深入,静电纺丝技术制备锂离子电池材料将更加成熟并取得更多的突破。     

The effects of atmosphere and calcined temperature on photocatalytic activity of TiO2 nanofibers prepared by electrospinning

TiO₂-based nanofibers were synthesized using a sol–gel method and electrospinning technique. The as-spun composite fibers were heat-treated at different temperatures (500°C, 550°C, 600°C, and 650°C) and atmospheres (ammonia and nitrogen) for 4 h. The fibers had diameters of 50 to 200 nm and mainly featured anatase and rutile phases. The anatase phase decreased and the rutile phase increased with increasing temperature. Different nitrogen conditions exerted minimal effects on the TiO₂ crystalline phase. Different nitriding atmospheres during preservation heating yielded various effects on fibers. The effect of nitrogen in ammonia atmosphere is better than that in nitrogen atmosphere. The fibers heat-treated at 600°C and subjected to preservation heating in NH₃ showed high photocatalytic activity.     

Polymeric nanofibers containing solid nanoparticles prepared by electrospinning and their applications

Generally, polymer solution or sol–gel is used to produce electrospun nanofibers via the electrospinning technique. In the utilized sol–gel, the metallic precursor should be soluble in a proper solvent since it has to hydrolyze and polycondensate in the final solution; this strategy straitens the applications of the electrospinning process and limits the category of the electrospinnable materials. In this study, we are discussing electrospinning of a colloidal solution process as an alternative strategy. We have utilized many solid nanopowders and different polymers as well. All the examined colloids have been successfully electrospun. According to the SEM and FE SEM analyses for the obtained nanofiber mats, the polymeric nanofibers could imprison the small nanoparticles; however, the big size ones were observed attaching the nanofiber mats. Successfully, the proposed strategy could be exploited to prepare polymeric nanofibers incorporating metal nanoparticles which might have interesting properties compared with the pristine. For instance, PCL/Ti nanofiber mats exhibited good bioactivity compared with pristine PCL. The proposed strategy can be considered as an innovated methodology to prepare a new class of the electrospun nanofiber mats which cannot be obtained by the conventional electrospinning technique.     

基于静电纺丝技术制备Cu2+掺杂TiO2纳米纤维的研究

以聚苯乙烯溶液为络合剂与钛酸丁脂/醋酸铜混合制得前驱体,采用静电纺丝法制得聚苯乙烯(PS)/钛酸丁脂[Ti(OC4H9)4]/醋酸铜[Cu(CH3COO)2·H2O]复合纤维,经焙烧后得到均一直径、具有较高比表面积和多孔结构的TiO2/CuO复合纳米纤维.对所制得的纳米纤维的结晶度、表面形貌,分别采用X射线粉末衍射、红外光谱( IR) 、扫描电镜(SEM) 等分析测试手段进行了表征.结果表明,煅烧温度、PS浓度、钛酸丁脂浓度对纤维的直径和形貌有很大影响.     

静电纺丝制备蛋清蛋白/聚氧化乙烯纳米纤维

本研究采用去离子水为溶剂,以蛋清蛋白与聚氧化乙烯（PEO）混合进行静电纺丝制备纳米纤维,采用扫描电镜表征了蛋清蛋白/PEO纳米纤维的形貌特征,探究了溶液质量分数以及纺丝工艺参数对蛋清蛋白/PEO纤维形貌的影响,并采用元素分析测试表征了纤维的元素组成成分。实验结果表明,蛋清在质量分数20%~80%之间表现出可纺性,蛋清质量分数50%的纺丝溶液进行纺丝,在纺丝电压25kV、纺丝距离16cm、挤出速度0.2mL/h的条件下,可纺性最好,制备的纤维无珠串平均直径为389nm,且纳米纤维中11.02%为氮元素,说明蛋清中的蛋白质成功转化为了纳米纤维。蛋清蛋白具有生物友好、可降解、来源广泛等优点,本研究成功实现了蛋清蛋白纳米纤维绿色制造,为其在生物医药、电池催化等领域的应用提供了基础。     

Photocatalytic properties of PMMA‐TiO2 class I and class II hybrid nanofibers obtained by electrospinning

The preparation, characterization, and photocatalytic activity evaluation of three hybrid fibrous materials composed mainly by poly(methyl methacrylate) (PMMA), methyl methacrylate (MMA): 3‐(trimethoxysilyl) propyl methacrylate (TMSPM): titanium butoxide (TBT), TiO₂ nanoparticles (NPTiO₂), and TiO₂ nanowires (NWTiO₂) is studied. Two types of fibe?s structures were prepared, single and core‐shell structures. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed both structures, single and core‐shell, as well as the inorganic phase were dispersed in the hybrid fibers. Infrared spectroscopic analysis (FT‐IR) and thermal analysis showed the organic and inorganic components, as well as the weight percentage of the inorganic phase present in hybrid fibers. The photocatalytic activity of the hybrid fibers class I and II showed that the best photodegradative efficiency for methylene blue in aqueous solution (2.9 × 10^?5 M) was 95%, provided by PMMA—10 wt % NPTiO₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44334.     

Needle and needleless electrospinning for nanofibers

A metallic needle is most often used in conventional electrospinning, where a point‐plate electric field with nonuniform distribution is formed in single‐needle electrospinning (SNE). Low flow rate in SNE has restricted the application of electrospinning on an industrial scale. Multiple needles have been introduced to enhance the flow rate. However, multiple needles make the electric field distribution much more complex. To resolve this problem, alternative electrospinning setups with more uniform electric field have to be developed. Flat spinnerets have been demonstrated to replace the needle in SNE setups. The operating diagrams for flat spinneret electrospinning (FSE) were determined and differed significantly from those for SNE. Nanofibers produced by FSE were more uniform than those from SNE. These differences were explained by the differences in electric fields simulated using finite element analysis (FEA). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010