P3HT修饰一维有序壳核式CdS/ZnO纳米棒阵列复合膜的光电化学性能

采用电化学方法在铟锡氧化物(ITO)导电玻璃上制备了高度有序的ZnO纳米棒阵列, 在ZnO纳米棒阵列上先后电化学沉积CdS纳米晶膜及聚3-己基噻吩(P3HT)薄膜得到P3HT修饰的一维有序壳核式CdS/ZnO纳米阵列结构, 并通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、能量散射X射线(EDX)等表征手段证实了该结构的形成. 以此纳米结构薄膜为光阳极组装新型半导体敏化太阳电池, 研究了CdS纳米晶膜的厚度和P3HT薄膜的沉积对电池光伏性能的影响, 初步探讨了电荷在电池结构中的传输机理, 结果表明, CdS纳米晶膜和P3HT薄膜的沉积有效地拓宽了光阳极的光吸收范围, 实验中电池的光电转换效率最高达到1.08%.     

二氧化锰纳米层的制备及电容性能研究

以Mn(NO3)2、Na OH和H2O2为原料,采用水热技术制备了Na型层状氧化锰(Na-Mn O2)。通过离子交换反应对NaMn O2进行了剥离,得到了氧化锰纳米层胶体分散液。将氧化锰纳米层分散液冷冻干燥后得到了氧化锰重组物(ERMn O2)。通过XRD、SEM和AFM对制备试样进行了分析表征。电化学测试结果表明,在1.0 mol·L-1Na2SO4水溶液中,当电流密度为0.25 A·g-1时,ERMn O2的质量比电容高达117 F·g-1远远高于其前驱物Na-Mn O2的比电容(79 F·g-1),并且表现出相似的循环稳定性。     

Textile fabricated biodegradable composite stents with core-shell structure

This study proposes composite stents with core–shell structure. Biodegradable polyvinyl alcohol (PVA) yarns are twisted and then coated with polycaprolactone/polyethylene glycol (PEG) blends. The coated yarns are weft knitted into braids and then thermally treated to form composite stents with core–shell structure. The morphological, mechanical, and biological characteristics of the formed composite stents are evaluated to determine the effects of PEG concentration. Results show that composite stents acquire the flexibility of PVA yarns and elasticity of weft knits. The presence of PEG positively influences composite stent performance. When the PEG concentration is 30 wt%, composite stents exhibit a compressive strength of 6.15 N and cell viability of 97.32% after a 24 h of culture. The selected materials are biodegradable, and the novel structure meets the requirements of bioresorbable vascular stent, which suggests that the proposed composite stents have good potential for advancement.     

Preparation and structure of novel siloxene nanosheets

We demonstrate the two-dimensional silicon backbone structure of siloxene nanosheets, which produces relatively monodisperse nanosheets with a thickness of 0.7 nm and lengths in the range 100-200 nm; the thickness is an order of magnitude smaller than that of previously reported silicon nanoparticles prepared by a variety of other methods.     

A template-free aqueous route to ZnO nanorod arrays with high optical property

A mild template-free aqueous route was successfully established to synthesize well-aligned ZnO nanorod arrays, which were proved to exhibit high optical property by PL spectra.     

Simple solvothermal route to synthesize ZnO nanosheets, nanonails, and well-aligned nanorod arrays

ZnO nanosheets, nanonails, and well-aligned nanorods were fabricated on Zn foils by a solvothermal approach using ethanol as the solvent. A lower synthesis temperature and a shorter time period favor the formation of nanosheets. By optimizing the synthesis temperature and time period, ZnO nanonails with a hexagonal cap and a long stem could be produced. A higher temperature was not favorable to produce uniform and smooth nanorods. Well-aligned ZnO nanorod arrays were produced with diameters within 100-250 nm and lengths up to approximately 6 microm when NaOH was added to the solvent. By optimizing the reaction parameters, the morphology, size, and orientation of the nanoforms could be tailored. The ZnO nanorods exhibit an excitonic strong UV emission and a defect-related broad green emission at room temperature. The defect-related green emission band decreased with the improvement of the degree of alignment of the nanorods.     

Preparation and optical properties of silica@Ag-Cu alloy core-shell composite colloids

The silica@Ag-Cu alloy core-shell composite colloids have been successfully synthesized by an electroless plating approach to explore the possibility of modifying the plasmon resonance at the nanoshell surface by varying the metal nanoshell composition for the first time. The surface plasmon resonance of the composite colloids increases in intensity and shifts towards longer, then shorter wavelengths as the Cu/Ag ratio in the alloy shell is increased. The variations in intensity of the surface plasmon resonance with the Cu/Ag ratio obviously affect the Raman bands of the silica colloid core. The report here may supply a new technique to effectively modify the surface plasmon resonance.     

镁铝复合氧化物载体的制备与性质研究

以硝酸镁和硝酸铝为原料,用氨水溶液作为pH调节剂,采用共沉淀法制备了镁铝复合氧化物载体,研究了制备过程中镁铝比、pH调节剂种类、水解过程pH值的大小、反应温度、焙烧温度及回流晶化温度对复合氧化物载体理化性质的影响。并以RFCC汽油加氢脱硫为探针反应,考察了以镁铝复合氧化物为载体的催化剂选择性加氢脱硫性能。实验结果表明,在镁铝分子比为10、反应温度为80℃、pH值为9.5条件下制备的镁铝复合氧化物载体具有适宜的比表面积和均匀的孔分布,且晶型较完整,结晶度高。以该复合氧化物为载体制备的催化剂具有良好的RFCC汽油选择性加氢脱硫反应性能。     

Effect of shell thickness on the temperature-sensitive property of core-shell composite polymer particles

Core-shell composite polymer particles having temperature-sensitive shell were prepared by seeded emulsion copolymerization of dimethylaminoethyl methacrylate and ethylene glycol dimethacrylate (EGDM) with 0.14 μ-sized polystyrene seed particles according to our previous article. In this article, the effects of crosslinking density and thickness of the shell on the temperature-sensitive property were studied. Two series of composite particles, one with various EGDM contents in the shell and the other with various shell contents, were prepared for this study. The composite particles at the EGDM content of 3 wt % with the shell content of 47 wt %, showed the maximum swelling and deswelling phenomena at temperatures, respectively, below and above the lower critical solution temperature. The adsorption and desorption behaviors of low molecular weight cationic emulsifier and bio-molecules were dependent on the shell content. In almost all cases, the adsorption/desorption behavior reached to the maximum variations at the shell content of 17 wt %. © 1996 John Wiley & Sons, Inc.     

Preparation of composite membranes with bicontinuous structure

Composite membranes with a hierarchical structure comprising thin regions with a bicontinuous structure and thick regions providing mechanical strength have been prepared by casting inorganic zeolite particles and mixtures that yield organic polymers onto substrates that were decorated with sessile droplets of aqueous solutions. Analysis by scanning electron microscopy (SEM) showed a membrane structure with well-ordered imprints caused by the sessile template droplets. These imprints were open at the bottom and covered on the top with a thin sheet composed of particles and polymer. The particles protruded out of the polymer sheet at the top and bottom of the membrane in the thin regions. A significant number of the particles protruded out of both interfaces at the same time. Thus, these parts of the membrane can be considered to be bicontinuous. The imprints are surrounded by thick regions. These regions act as a supporting structure. Thus, the membranes are stable enough to be handled without special precautions and might be applicable to membrane separation processes.     

Preparation and properties of Ni-doped ZnO rod arrays from aqueous solution

Ni-doped ZnO rod arrays were successfully prepared on glass substrate from the aqueous solution at a temperature of 80 °C. The densities, diameters, and lengths of the rods can easily be well controlled through the concentrations of dopants, and the dopant Ni ions were incorporated into the wurtzite-structure of ZnO crystal. Room temperature photoluminescence spectrum of rod arrays show a strong emission band at 410 nm, and the oxygen deficiencies in ZnO structures were significantly reduced with Ni doped in ZnO rod arrays. The field dependence of magnetization measured at room temperature exhibited the obvious ferromagnetic properties.