AZO@C柔性纳米纤维的制备与性能

以聚乙烯醇(PVA)为原料,成功制备了新型掺铝氧化锌包覆碳结构(AZO@C)的柔性纳米纤维。首先通过静电纺丝制备PVA初生纳米纤维,经过热处理工艺提高纳米纤维的耐水性,然后采用水热合成法在其表面包覆一层锌铝氢氧化物,再经过在500℃高温条件下烧结,PVA表面包覆的锌铝氢氧化物发生脱水反应形成致密的掺铝氧化锌(AZO)纳米粒子,同时PVA纳米纤维在高温煅烧中被炭化,形成一种新型AZO@C纳米复合材料。采用红外光谱(FT-IR)、热重分析仪(TGA)、扫描电镜(SEM)等对纳米纤维结构与性能进行测试及表征,AZO@C纳米纤维的平均直径为(320±45)nm。并通过太阳光下降解甲基橙实验证明了AZO@C柔性纳米纤维的光催化降解性能。     

壳聚糖/聚乙烯醇复合纳米导电纤维的制备及性能表征

以壳聚糖(CS)、聚乙烯醇(PVA)和纳米石墨粉(G)为原料,利用静电纺丝技术分别制备了壳聚糖/聚乙烯醇共混纳米纤维及壳聚糖/聚乙烯醇/纳米石墨粉复合纳米纤维,采用原位聚合法在纤维表面聚合导电聚合物聚苯胺,得到具有优良导电性能的聚合CS/PVA和聚合CS/PVA/G复合纳米纤维。通过扫描镜、X射线衍射、红外光谱等测试手段对纤维的形貌和结构进行表征。结果表明,聚苯胺均匀包覆在经原位聚合的复合纳米纤维表面,提高了纤维的导电性能,纳米石墨粉与聚苯胺形成插入化合物进一步提高了纤维的导电性能。     

海水可降解Fe3O4@PVA/PLGA复合膜的制备及性能

以纳米四氧化三铁(Fe3 O4 )催化剂为芯材,水溶性聚乙烯醇(PVA)为壳材,制备以溶解为触发条件的 Fe3 O4@PVA微胶囊催化剂,并将此微胶囊催化剂负载于聚乳酸-羟基乙酸(PLGA)膜中,制备淡水/海水可降解的 Fe3 O4@PVA/PLGA复合膜.采用透射电子显微镜(TEM)和动态光散射(DLS)粒径分布对 Fe3 O4@PVA核壳结构粒子的形态进行表征,其壳层厚度为 2～3 nm.通过傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)、热重分析(TG)、磁滞回线测试(VSM)、电子万能材料实验等手段明确 Fe3 O4@PVA核壳结构粒子和 Fe3 O4@PVA/PLGA复合膜的结构特征、磁学及力学性能.讨论 Fe3 O4@PVA/PLGA复合膜在淡水、海水、空气、黑暗和低温环境下的降解性能.结果表明:Fe3 O4@PVA/PLGA复合膜在海水中 120 天的最大降解率为 97.79%,在淡水中 120 天的最大降解率为 99.75%.Fe3 O4@PVA/PLGA复合膜在海水中被降解,质均分子量由 28440 降为 1396.     

异质结型NiO/ZnO复合纳米纤维的制备及光催化性能

采用静电纺丝技术, 以聚乙烯醇(PVA)和醋酸锌[Zn(CH₃COO)₂]为前驱体, 制备纯ZnO纳米纤维, 并以其为基质, 醋酸镍为镍源, 通过溶剂热法制备了NiO/ZnO复合纳米纤维. 利用X射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)和荧光光谱(PL)等分析测试手段对样品的结构和形貌进行表征。以罗丹明Ｂ的脱色降解为模式反应, 考察了样品的光催化性能。结果表明: NiO粒子均匀地负载到ZnO纳米纤维上, 得到了异质结型NiO/ZnO复合纳米纤维光催化材料, 与纯ZnO纳米纤维相比光催化活性明显提高, 且易于分离、回收和再利用。循环使用3次, RB的脱色率仍保持在89%以上。     

PAN/AZO复合导电纤维的制备与性能

以硝酸锌和硝酸铝为原料,采用共沉积,经高温烧结制得导电掺铝氧化锌(AZO)纳米颗粒,并将导电AZO纳米粉体添加到聚丙烯腈(PAN)纺丝液中,利用湿法纺丝技术制备了结构完整的PAN/AZO复合导电纤维。采用X射线衍射仪、热重分析仪、扫描电子显微镜及Electrometer电阻测试仪分别对其性能结构进行表征。结果表明:AZO纳米粉体的添加使PAN纤维的结构稳定性得到提高,PAN/AZO复合导电纤维的电阻率降低了1~2个数量级。     

ZnO纳米棒Al掺杂和A1,N共掺杂的制备技术与光致发光性能

采用水热法首先合成了Al掺杂ZnO(AZO)纳米棒,在此基础上通过550℃的氨气氛中退火制备了Al,N共掺杂ZnO(ANZ())纳米棒.运用X射线衍射(XRD),场发射扫描电镜(FESEM),透射电子显微镜(TEM),X射线能谱(EDS)和光致发光(PL)对样品进行了表征与分析.结果表明,制备的AZO和ANZ()纳米棒...     

AZO中空纳米纤维的制备及性能

中空纳米纤维因其比表面积大、密度小等特性近年来备受关注。通过静电纺丝制得聚乙烯醇(PVA)纳米纤维,并采用水热合成法在经热处理的PVA纳米纤维表面包覆一层锌铝氢氧化物,再经高温煅烧处理成功制得掺杂铝元素的氧化锌(AZO)中空纳米纤维。通过扫描电镜、热重分析仪进行测试表征,结果表明所得产物具有明显的中空结构,并对甲基橙有光催化降解性能。     

电纺十二酸十二酯@聚乙烯醇蓄热调温纤维的制备及性能

以十二酸十二酯作为相变材料(PCM),以聚乙烯醇(PVA)作为支撑材料,通过乳液静电纺丝技术制备十二酸十二酯@PVA蓄热调温纤维。应用SEM、TEM、DSC、TGA、迷你温度记录仪和红外热成像仪等研究了纺丝液组成及静电纺纤维的表面形貌、潜热值、热稳定性、调温性能、力学性能和水溶性。结果表明,当PVA浓度为10.0wt%、十二酸十二酯∶PVA质量比为50%时,纺丝液具有较好的稳定性和可纺性。十二酸十二酯@PVA静电纺纤维具有明显的芯-鞘结构,纤维中PCM的热分解温度比纯PCM提高了20℃,具有良好的热稳定性。十二酸十二酯@PVA静电纺纤维的潜热值在63 J/g左右,在降温冷却和热红外成像测试中,显示出良好的蓄热调温性能。经戊二醛交联后,静电纺纤维中支撑材料的热稳定性显著增强,而且,纤维的力学性能和水溶解性得到明显改善。      

超临界抗溶剂法纳米Al_2O_3-ZrO_2颗粒的制备与表征

以CO2为抗溶剂介质,无水乙醇为溶剂,采用超临界抗溶剂法(SAS)制备了纳米Al2O3-ZrO2复合氧化物颗粒的前驱体—纳米Al(NO3)3-Zr(NO3)4颗粒,系统考察了温度和压力等因素对制备过程的影响,并对前驱体中Al、Zr组分的共抗溶剂效应进行了研究,通过焙烧前驱体Al(NO3)3-Zr(NO3)4制得了纳米Al2O3-ZrO2球形颗粒.采用热重质谱(TG-MS)、X射线衍射(XRD)、X射线光电子能谱(XPS)、场发射透射电镜(FEG-TEM)和程序升温还原(TPR)等技术对所制备的前驱体Al(NO3)3-Zr(NO3)4和Al2O3-ZrO2纳米颗粒的物化性能进行了表征,初步考察了Al2O3-ZrO2纳米颗粒负载Ni催化剂的还原性能.研究发现,该纳米复合氧化物比用浸渍?沉淀法制得的Al2O3-ZrO2载体对活性组分Ni具有更好的分散性能,作为新型催化剂载体材料有良好的应用前景.     

水热合成制备纳米铁酸铜及其表征

为获得粒径小且分布均匀的铁酸铜(CuFe2O4)粉体,本文中以硝酸铜、硝酸铁及氢氧化钠为反应原料,采用水热法合成了纳米CuFe2O4粉体,研究了前驱体组分、反应温度、保温时间和表面活性剂聚乙烯醇(PVA)对CuFe2O4粉体制备的影响;用X射线衍射(XRD)、粒度分析仪、扫描电子显微镜(SEM)和红外光谱(IR)等分析方法对样品进行了表征。结果表明,前驱体中NO3-的存在将导致产物中铁酸亚铜CuFeO2的产生;在反应温度为320℃、以PVA作分散剂、保温3h的水热条件下可合成纳米CuFe2O4粉体。     

Fabrication and luminescence of YF3:Tb3+ hollow nanofibers

YF₃:Tb³⁺ hollow nanofibers were successfully fabricated via fluorination of the relevant Y₂O₃:Tb³⁺ hollow nanofibers which were obtained by calcining the electrospun PVP/[Y(NO₃)₃ + Tb(NO₃)₃] composite nanofibers. The morphology and properties of the products were investigated in detail by X-ray diffraction, scanning electron microscope, transmission electron microscope, and fluorescence spectrometer. YF₃:Tb³⁺ hollow nanofibers were pure orthorhombic phase with space group Pnma and were hollow-centered structure with the mean diameter of 148 ± 23 nm. Fluorescence emission peaks of Tb³⁺ in the YF₃:Tb³⁺ hollow nanofibers were observed and assigned to the energy levels transitions of ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3) (490, 543, 588, and 620 nm) of Tb³⁺ ions, and the ⁵D₄ → ⁷F₅ hypersensitive transition at 543 nm was the dominant emission peak. Moreover, the emitting colors of YF₃:Tb³⁺ hollow nanofibers were located in the green region in CIE chromaticity coordinates diagram. The luminescent intensity of YF₃:Tb³⁺ hollow nanofibers was increased remarkably with the increasing doping concentration of Tb³⁺ ions and reached a maximum at 7 mol% of Tb³⁺. The possible formation mechanism of YF₃:Tb³⁺ hollow nanofibers was also discussed. This preparation technique could be applied to prepare other rare earth fluoride hollow nanofibers.     

Nanoscale azo pigment immobilized on carbon nanotubes via liquid phase reprecipitation approach

Nanoscale azo pigment immobilized on the outer shell of multiwalled carbon nanotubes (MWCNT–AZO) were prepared by modified liquid phase reprecipitation method, and the MWCNT–AZO hybrid was characterized by means of TEM, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–VIS absorption. The photoconductivity of single-layered photoreceptors, where MWCNT–AZO served as the charge generation material (CGM), was studied by the xerographic photoinduced discharge method. The results indicated that the MWCNT–AZO nano hybrid showed broader and enhanced photosensitivity than MWCNT/bulk azo pigments (AZO) blend or the bulk AZO did, which was interpreted in terms of nanometer size effect of MWCNT–AZO hybrid and charge transfer from AZO nanoparticles to MWCNT.     

Porous FeS nanofibers with numerous nanovoids obtained by Kirkendall diffusion effect for use as anode materials for sodium-ion batteries

Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation.The post-treatment of the as-spun Fe(acac)3-polyacrylonitrile composite nanofibers in an air atmosphere yielded hollow Fe2O3 nanofibers due to Ostwald ripening.The ultrafine Fe2O3 nanocrystals formed at the center of the fiber diffused toward the outside of the fiber via Ostwald ripening.On sulfidation,the Fe2O3 hollow nanofibers were transformed into porous FeS nanofibers,which contained numerous nanovoids.The formation of porosity in the FeS nanofibers was driven by nanoscale Kirkendall diffusion.The porous FeS nanofibers were very structurally stable and had superior sodium-ion storage properties compared with the hollow Fe2O3 nanofibers.The discharge capacities of the porous FeS nanofibers for the 1st and 150th cycles at a current density of 500 mA.g-1 were 561 and 592 mA.h·g-1,respectively.The FeS nanofibers had final discharge capacities of 456,437,413,394,380,and 353 mA.h.g-1 at current densities of 0.2,0.5,1.0,2.0,3.0,and 5.0 A.g-1,respectively.     

Fabrication and luminescence properties of YF3:Eu3+ hollow nanofibers via coaxial electrospinning combined with fluorination technique

Polyvinyl pyrrolidone (PVP)–PVP/[Y(NO₃)₃ + Eu(NO₃)₃] core–sheath composite nanofibers were prepared by coaxial electrospinning, and then Y₂O₃:Eu³⁺ hollow nanofibers were synthesized by calcination of the as-prepared composite nanofibers. For the first time, YF₃:Eu³⁺ hollow nanofibers were successfully fabricated by fluorination of the Y₂O₃:Eu³⁺ hollow nanofibers via a double-crucible method using NH₄HF₂ as fluorinating agent. The morphology and properties of the products were investigated in detail by X-ray diffraction, scanning electron microscope (SEM), transmission electron microscope (TEM), and fluorescence spectrometer. YF₃:Eu³⁺ hollow nanofibers were pure orthorhombic phase with space group Pnma and were hollow-centered structure with the mean diameter of 211 ± 29 nm. Fluorescence emission peaks of Eu³⁺ in the YF₃:Eu³⁺ hollow nanofibers were observed and assigned to the energy levels transitions of ⁵D₀ → ⁷F₁ (587 and 593 nm), ⁵D₀ → ⁷F₂ (615 and 620 nm), and the ⁵D₀ → ⁷F₁ hypersensitive transition at 593 nm was the dominant emission peak. Moreover, the emitting colors of YF₃:Eu³⁺ hollow nanofibers were located in the red region in CIE chromaticity coordinates diagram. The luminescent intensity of YF₃:Eu³⁺ hollow nanofibers was increased remarkably with the increasing doping concentration of Eu³⁺ ions and reached a maximum at 7 mol% of Eu³⁺. This preparation technique could be applied to prepare other rare earth fluoride hollow nanofibers.     

Coaxial electrospinning fabrication and electrochemical properties of LiFePO4/C/Ag composite hollow nanofibers

LiFePO₄/C/Ag composite hollow nanofibers were synthesized by calcination of the coaxial electrospun nanofibers with polyvinyl pyrrolidone (PVP) as core and [LiOH + Fe(NO₃)₃ + H₃PO₄]/PVP/AgNO₃ as shell. PVP was used as the electrospinning template and carbon source. During the calcination, LiFePO₄ precursor was transformed to LiFePO₄ while AgNO₃ and PVP were decomposed into silver and carbon. The morphology and properties of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, BET specific surface area analysis, electrochemical impedance spectroscopy and galvanostatic charge–discharge measurements. The results indicate that the mean diameter of as-prepared LiFePO₄/C/Ag composite hollow nanofibers is 154.5 ± 18.6 nm and the BET specific surface area is 119.14 m² g^?1. The addition of silver and carbon does not affect the structure of LiFePO₄, but improves its electrochemical performances. At the current density of 0.2 C, the initial discharge capacity of LiFePO₄/C/Ag hollow nanofibers electrode is 138.71 mAh g^?1, which is higher than that of LiFePO₄/C nanofibers electrode. The improved specific capacity may be attributed to increase electrode conductivity after the introduction of silver. The formation mechanism of the LiFePO₄/C/Ag composite hollow nanofibers was also proposed.     

Growth of carbon nanofibers and related structures by combined method of plasma enhanced chemical vapor deposition and aerosol synthesis

Growth of carbon nanofibers and nanotubes by combination of aerosol synthesis and plasma-enhanced catalytic chemical vapor deposition with alcohol as carbon precursor is presented. Only a hollow cathode glow discharge (HCGD) is used as gas activation process without any specific heating of the substrate. Specially designed hollow cathode enables the evaporation of catalyst directly on the substrate for catalytic growth. Product of physical vapor deposition process was examined by energy dispersive X-ray spectrometer (EDS). Spectroscopic features of the plasma were monitored by optical emission spectroscopy (OES). Carbon deposition was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Catalytic nanofibers and multi-walled carbon nanotubes with outer diameters 20-60 nm have been observed.     

静电纺丝法制备陶瓷中空纳米纤维的研究进展

陶瓷中空纳米纤维具有特殊的纳米一维管式结构, 在微电子、应用催化、气体传感器和光电转换等领域具有良好的应用前景。本文综述了静电纺丝法制备陶瓷中空纳米纤维的最新研究进展, 主要包括同轴静电纺丝法、单针头静电纺丝法以及后处理法在制备陶瓷中空纳米纤维方面的发展趋势, 重点介绍了单针头静电纺丝法在制备中空纳米结构上存在的相转化、气体挥发和柯肯达尔效应等机理, 并且对于陶瓷中空纳米纤维的应用前景以及不足进行了展望与总结。     

不同缓冲层对Al掺杂ZnO薄膜性能的影响

本文采用射频反应磁控溅射法在玻璃基底上分别以Al2O3和AZO为缓冲层制备ZnO:Al(AZO)薄膜,利用X射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见分光光度计等方法对薄膜的结构和光电性能进行表征。XRD和SEM的分析结果表明,在Al2O3和AZO缓冲层上生长的AZO薄膜均具有较好的C轴择优取向,薄膜表面光滑平整,薄膜的结晶质量得到改善;透射光谱表明所有样品在可见光范围内的透过率均超过80%;薄膜的导电性能得到提高。     

Transparent conductive and infrared reflective AZO/Cu/AZO multilayer film prepared by RF magnetron sputtering

AZO/Cu/AZO multilayer films were prepared on glass substrate by radio frequency magnetron sputtering technology. The prepared films were investigated by a four-point probe system, X-ray diffraction, optical transmittance spectra, scanning electron microscope, atomic force microscopy and Fourier transform infrared spectroscopy. The results showed that Cu inner layer started forming a continuous film at the thickness around 11 nm. The prepared AZO/Cu/AZO samples exhibited the visible transmittance of 60–80 % and sample with 15 nm Cu inner layer showed the highest infrared reflection rate of 67 % in FIR region and the lowest sheet resistance of 16.6 Ω/sq. The proper visible transmittance and infrared reflection property of the AZO/Cu/AZO multilayer film make it a promising candidate for future energy conservation materials.