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51.
52.
同轴静电纺丝技术制备Y2O3:Eu3+@SiO2豆角状纳米电缆与表征 总被引:1,自引:0,他引:1
采用同轴静电纺丝技术, 以氧化钇、氧化铕、正硅酸乙酯(C8H20O4Si)、无水乙醇、PVP和DMF为原料, 成功制备出大量的Y2O3:Eu3+@SiO2豆角状纳米电缆. 用TG-DTA, XRD, SEM, TEM和荧光光谱等分析技术对样品进行了系统地表征. 结果表明, 得到的产物为Y2O3:Eu3+@SiO2豆角状纳米电缆, 以无定型SiO2为壳层, 晶态Y2O3:Eu3+球为芯, 电缆直径约为200 nm, 内部球平均直径约150 nm, 壳层厚度约为25 nm, 电缆长度>300 μm. 纳米电缆内部为球状结构, 沿着纤维长度方向有序排列, 形貌均一. Y2O3:Eu3+@SiO2豆角状纳米电缆在246 nm紫外光激发下, 发射出Eu3+离子特征的波长为614 nm的明亮红光. 对其形成机理进行了初步讨论. 相似文献
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采用静电纺丝技术和水热合成法制备了CeO2/TiO2复合纳米纤维. 利用X射线衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)和比表面积测定(BET)等分析测试手段对样品的形貌及结构进行了表征, 并以罗丹明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: CeO2纳米粒子均匀地生长在TiO2纳米纤维表面, 形成了异质结构的CeO2/TiO2复合纳米纤维光催化材料. 通过改变碱源, 可以得到不同形貌的CeO2. CeO2的存在增加了TiO2纳米纤维的比表面积, 有效地实现TiO2光生电子和空穴的分离, 增强了体系的量子效率, 与纯TiO2纳米纤维相比光催化活性明显提高. 初步探讨了异质结的形成机理. 相似文献
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实验设计以硅酸铝为实体框架、十二烷基乙氧基磺基甜菜碱(OSB-12)为功能有机物, 通过共沉淀法合成同时吸附阴、阳离子染料的纳米材料. 借助FT-IR, SEM以及比表面孔隙分析等多种手段表征该吸附材料的结构、形貌. 材料通过静电纺丝制备成微米纤维, 解决了材料的便捷、完全回收问题, 且对阴、阳离子染料均有良好吸附效果, 吸附速率快. 结果表明, 弱酸性桃红B和碱性艳蓝BO吸附量分别达到471和847 mg/g, 论文详细讨论了染料的吸附机理, 电荷作用在离子型染料吸附过程中起主导作用, 即包埋在材料中的两性表面活性剂OSB-12发挥着离子交换的功能. 从染料去除率和材料分离性能等可以预见, 该材料在实际染料废水处理中体现了良好的应用潜力. 相似文献
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Nikoo Saveh‐Shemshaki Masoud Latifi Roohollah Bagherzadeh Mahdi Malekshahi Byranvand Naimeh Naseri Ali Dabirian 《先进技术聚合物》2016,27(3):358-365
Iron(III) oxide (hematite, Fe2O3) nanofibers, as visible light‐induced photoanode for water oxidation reaction of a water splitting process, were fabricated through electrospinning method followed by calcination treatment. The prepared samples were characterized with scanning electron microscopy, and three‐electrode galvanostat/potentiostat for evaluating their photoelectrochemical (PEC) properties. The diameter of the as‐spun fibers is about 300 nm, and calcinated fibers have diameter less than 110 nm with mesoporous structure. Optimized multilayered electrospun α‐Fe2O3 nanostructure mats showed photocurrent density of 0.53 mA/cm2 under dark and visible illumination conditions at voltage 1.23 V and constant intensity (900 mW/cm2). This photovoltaic performance of nanostructure mats makes it suitable choice for using in the PEC water splitting application as an efficient photoanode. This method, if combined with appropriate flexible conductive substrate, has the potential for producing flexible hematite solar fuel generators. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
57.
Synthesis and characterization of poly (acrylonitrile‐co‐acrylic acid) as precursor of carbon nanofibers 下载免费PDF全文
Synthesis of a co‐polymer of polyacrylonitrile (PAN) producing a carbon nanofiber out of PAN and co‐polymer of PAN and comparison between these products were examined. Free‐radical solution copolymerization of acrylonitrile (AN) with acrylic acid (AA) was studied. In this perspective, AA, and AN were used as a precursor for polymerization reactions; then copolymers were synthesized by using ammonium persulfate (APS) as an oxidant and carried in water/dimethylformamide (DMF) mixture. These polymers were used to obtain corresponding electrospun nanofibers. Synthesized P(AN‐co‐AA) was investigated by Fourier transform infrared spectroscopy‐attenuated total reflection (FTIR‐ATR) spectroscopy, and characteristic peaks for AN unit, AA were achieved. Thermal behavior was examined by using differential scanning calorimeter (DSC) and thermal gravimetric analyzer (TGA), and results indicated that addition of monomers to AN unit reduced the Tg value of homopolymer PAN compared to P(AN‐co‐AA), which provides improvement to the cyclization and the formation of a thermally stable aromatic ladder polymer chain formation. In order to prevent the shrinkage and maintain the molecular orientation on nanofiber webs during stabilization, tension was applied to the samples, and thermal oxidation varies at 200–300°C for different duration of times. Surface morphology of the fibers was observed with scanning electron microscope (SEM), and average nanofiber diameter was found 550 nm, and after carbonization it was reduced to 320 nm for homopolymer PAN, and for poly(AN‐co‐AA) average nanofiber diameter was found as 220 nm and reduced to 130 nm, respectively. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
58.
采用溶剂热法合成了以锆为金属核心、2-氨基为配体的锆基金属有机骨架(UiO-66)纳米材料,通过静电纺丝技术制备出UiO-66自由分散的聚丙烯腈(PAN/UiO-66)纤维,可控热解得到多孔碳纳米纤维(porous carbon nanofibers,PCNFs),结合湿化学还原法在PCNFs表面沉积Pd纳米颗粒,得到PCNFs@Pd复合材料。通过扫描电子显微镜、透射电子显微镜、X射线衍射技术对其形貌、组成、结构进行表征;采用电化学工作站分别测试了PCNFs@Pd在0.1 mol·L-1KOH和0.1 mol·L-1HClO4电解质中氧还原性能(oxygen reduction reaction,ORR)。结果表明,在PAN纤维中添加UiO-66显著提高了PCNFs@Pd(Pd负载量为0.34%)复合材料的ORR性能。相比40%Pt/C,在碱性电解质中,PCNFs@Pd复合材料展示出更低的Tafel斜率、更优异的循环稳定性和耐甲醇中毒性。在酸性电解质中也表现出类似20%Pt/C的催化活性和循环稳定性。 相似文献
59.
Shaocheng Wang Siyong Lin Bo Xue Chenyu Wang Nana Yan Yueyan Guan Yuntao Hu Xuejun Wen 《Molecules (Basel, Switzerland)》2022,27(4)
Background: This study aimed to develop an ultrathin nanofibrous membrane able to, firstly, mimic the natural fibrous architecture of human Bruch’s membrane (BM) and, secondly, promote survival of retinal pigment epithelial (RPE) cells after surface functionalization of fibrous membranes. Methods: Integrin-binding peptides (IBPs) that specifically interact with appropriate adhesion receptors on RPEs were immobilized on Bruch’s-mimetic membranes to promote coverage of RPEs. Surface morphologies, Fourier-transform infrared spectroscopy spectra, contact angle analysis, Alamar Blue assay, live/dead assay, immunofluorescence staining, and scanning electron microscopy were used to evaluate the outcome. Results: Results showed that coated membranes maintained the original morphology of nanofibers. After coating with IBPs, the water contact angle of the membrane surfaces varied from 92.38 ± 0.67 degrees to 20.16 ± 0.81 degrees. RPE cells seeded on IBP-coated membranes showed the highest viability at all time points (Day 1, p < 0.05; Day 3, p < 0.01; Days 7 and 14, p < 0.001). The proliferation rate of RPE cells on uncoated poly(ε-caprolactone) (PCL) membranes was significantly lower than that of IBP-coated membranes (p < 0.001). SEM images showed a well-organized hexa/polygonal monolayer of RPE cells on IBP-coated membranes. RPE cells proliferated rapidly, contacted, and became confluent. RPE cells formed a tight adhesion with nanofibers under high-magnification SEM. Our findings confirmed that the IBP-coated PCL membrane improved the attachment, proliferation, and viability of RPE cells. In addition, in this study, we used serum-free culture for RPE cells and short IBPs without immunogenicity to prevent graft rejection and immunogenicity during transplantation. Conclusions: These results indicated that the biomimic BM-IBP-RPE nanofibrous graft might be a new, practicable approach to increase the success rate of RPE cell transplantation. 相似文献
60.
计算了两共轴均匀带电圆环的相互作用能,并求出它们之间的相互作用力,绘制出电场力的空间分布图,进而讨论了作用力和两圆环半径和中心距离等参量的关系. 相似文献