光触媒空气滤纸及其性能研究

主要介绍了光触媒材料二氧化钛的发展及特性,讨论了光触媒空气过滤纸的加工工艺及杀菌消毒除臭性能实验,结果表明TiO2光触媒空气过滤纸具有明显的抗菌杀毒除臭的效果,是良好的环境卫士。     

掺Ni2+金红石型SnO2纳米粒子的制备及表征

采用化学共沉淀法制备掺Ni2+的SnO2纳米粉体。研究表明,不同pH下得到的样品均为四方相金红石型结构的SnO2,在pH=5时,Ni2+的利用率出现极大值99.97%;升高煅烧温度或延长煅烧时间,样品结晶程度都会随之增高,同时晶粒尺寸也呈现增大的趋势;所得样品呈球形,粒径约为60 nm。将掺Ni2+的SnO2粉体涂于白云母表面制成元件,测试粉体的电性能以及气敏性能,结果表明,在温度由30℃上升到150℃的过程中,元件电阻从33.1 kΩ近似线性地降低到4.8 kΩ;H2体积分数越大,元件对其敏感程度越高。     

碳纳米管场发射冷阴极的低温制备及场发射性能

利用纳米银的低温熔接性和良好导电性,研究了以纳米银取代传统的有机粘结剂和导电银浆制备CNTs场发射冷阴极的新工艺.将CNTs、纳米银、粘性松油醇和有机溶剂混合研磨后涂敷在镀Cu玻璃基片上,250℃烧结30min后,纳米银颗粒之间互相熔接,将周围的CNTs粘结成为整体膜,形成了表面平整、导电性和场发射性能良好的CNTs阴极.测量了不同纳米银掺入量的CNTs阴极的场发射性能,结果表明:当CNTs:Ag质量比率为1:1时,CNTs阴极具有最好的场发射性能,阈值电场为4.9V/μm,当电场强度为5.7V/μm时,场发射电流密度为41mA/cm2.纳米银比例过大,烧结后CNTs被熔接的银膜覆盖,高电压时场发射电流明显下降,而纳米银掺入量太少则会导致CNTs阴极的附着力和导电性变差.     

低压化学气相沉积法制备单壁碳纳米管

采用低压化学气相沉积(CVD)技术在MgO载体中的Fe、Co等纳米催化颗粒上制备碳纳米管(CNTs)，用高分辨透射电子显微镜(HRTEM)及喇曼光谱仪(Raman)对生长的CNTs结构特性进行了分析研究，结果表明制备的样品中虽含多壁碳纳米管，但单壁碳纳米管(SWNTs)居多，直径约为0．6～2nm．分布均匀，且既包含金属型管，也包含半导体型管。低压MgO载体CVD制备技术，大大增加了等量Fe、Co等催化反应颗粒的比表面积和反应活性，制备的单壁管产额大、成本低、CNTs更易于提纯。     

The effect of elastomeric nano-particles on the mechanical properties and crystallization behavior of polypropylene

Generally, toughness of polypropylene (PP) is an issue which has been investigated for many years to search for improvements. A traditional approach is to blend with rubber particles to enhance the toughness of PP yet modulus of PP decreases accordingly. Recently, we have achieved a good balance of toughness and stiffness of PP via blending PP with a small amount of elastomeric nano-particles (ENP). Based on our measurements, mechanical properties of the blends studied both the toughness of PP at room temperature and at −20 °C show substantial increase. On the other hand, the stiffness of the PP blends retains or even possesses a slight enhancement. One of the reasons for this improvement is due to the fact that the ENP is not only a toughening modifier but also a nucleation agent for the PP. The nucleation density of the blends increases, while the crystallization kinetics of the blends becomes faster compared with the pure PP samples.     

碱处理对纳米改性涤纶形态和松弛特性影响

将聚酯切片在熔融纺丝过程中添加纳米微粒制成的纳米改性涤纶进行碱处理,探讨了碱处理对纳米改性涤纶的表面形态、常规力学性能指标、力学松弛特征和拉伸柔量的影响。结果表明,碱处理后纳米改性涤纶表面产生微孔,其纤维断裂强伸度和断裂比功比碱处理前纳米改性涤纶小,应力松弛和蠕变现象比碱处理前纳米改性涤纶更明显、更易发生;碱处理后纳米改性涤纶的拉伸柔量要比碱处理前纳米改性涤纶的大。     

含Pd-PdO纳米涂层钛阳极的电催化活性研究

从提高钛阳极在析氯环境的电催化活性出发,用溶胶-凝胶法制备了纳米级Pd-PdO/Ti涂层钛阳极。采用XRD分析了涂层的成分及相结构,测试不同烧结温度获得的阳极的电极电位和循环伏安曲线。研究结果表明,Pd-PdO/Ti涂层钛阳极具有极高的析氯电催化活性。     

多孔道磁金复合纳米粒子(Fe_3O_4-Au/pSiO_2)的制备及结构表征

采用分步包覆法制备了具有多核壳结构的磁金复合纳米粒子Fe3O4-Au/pSiO2,所得纳米粒子单分散性好,粒径较均匀,平均粒径为150nm。经过表面保护刻蚀处理后,粒子包覆层呈多孔道结构,平均孔径为7.3nm。由于多孔道包覆层的存在,磁金复合纳米粒子出现了位于536nm处金的表面等离子体共振峰,表明其具有一定的光通透性。与未刻蚀纳米粒子相比,刻蚀后的多孔道纳米粒子的饱和磁化强度提高了13.3emu/g,达到49.6emu/g。     

Characterization of carbon-supported platinum nano-particles synthesized using magnetron sputtering for application in PEM electrochemical systems

An innovative approach to the synthesis of nanostructured carbon-supported platinum electrocatalysts for application in proton-exchange membrane (PEM) electrochemical systems has been developed. Platinum nano-particles were deposited onto the carbon carrier using magnetron-ion sputtering. A special device has been developed to promote the effective stirring of the carbon carrier during catalyst deposition. Electrocatalytic powders thus obtained have been analyzed using XRD and TEM. The electrochemical performances of Pt/C based electrodes were studied in liquid electrolyte and in single-cell PEM fuel cell and water electrolyzer. Adjustment of sputtering process parameters (discharge power, sputtering time, bias voltage) led to the formation of electrocatalysts of high active surface area (up to 44 m² g⁻¹), high chemical purity and high electrochemical activity. A qualitative correlation between sputtering parameters and characteristics of electrocatalysts was established.     

无机纳米粒子增韧环氧树脂研究进展

环氧树脂是一类广泛应用的热固性树脂,在造纸工业中主要用作增强剂或者改性剂。然而其质脆,限制了它的进一步开发应用。在环氧树脂基体里添加无机纳米粒子是增韧环氧树脂的一种重要手段。本文综述了无机纳米粒子在环氧树脂基体内的分散方法、无机粒子增韧环氧树脂对环氧树脂的各种性能影响,分析了粒子粒径大小、含量及形态对增韧环氧树脂性能的影响并阐述了无机粒子增韧环氧树脂的机理。