Effect of a surface treatment for LiNi<Subscript>1/3</Subscript>Co<Subscript>1/3</Subscript>Mn<Subscript>1/3</Subscript>O<Subscript>2</Subscript> cathode material in lithium secondary batteries

LiNi_1/3Co_1/3Mn_1/3O₂ cathode material was surface-treated to improve its electrochemical performance. Al₂O₃ nanoparticles were coated onto the surface of LiNi_1/3Co_1/3Mn_1/3O₂ powder using a sol-gel method. The as-prepared Al₂O₃ nano-particle was identified as the cubic structure of Al₂O₃. XRD showed that the LiNi_1/3Co_1/3Mn_1/3O₂ structure was not affected by the Al₂O₃ coating. With a coating of 3 wt.% Al₂O₃ on LiNi_1/3Co_1/3Mn_1/3O₂, the cyclic-life performance and rate capability were improved. However, heavier coatings (5 wt.%) on LiNi_1/3Co_1/3Mn_1/3O₂ resulted in a considerable decrease of the discharge capacity and rate capability. The thermal stability of LiNi_1/3Co_1/3Mn_1/3O₂ materials was greatly improved by the 3 wt.% Al₂O₃ coating.     

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。     

Efficient tuning of the Pt nano-particle mono-dispersion on Vulcan XC-72R by selective pre-treatment and electrochemical evaluation of hydrogen oxidation and oxygen reduction reactions

The effect of chemical pre-treatment of the carbon support used for deposition of Pt nano-particles is reported. Data on particle size, distribution and their electocatalytic activity toward hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) are reported. Vulcan XC-72R carbon was pre-treated with 5% HNO₃, 0.07 M H₃PO₄, 0.2 M KOH and 10% H₂O₂. The properties of carbon supports were studied by N₂ adsorption and X-ray photoelectron spectroscopy (XPS). Chemical reduction with ethylene glycol (EG) was used to synthesize Pt on carbon supports and the differences in catalyst morphology were characterized using CO chemisorption, X-ray diffraction, energy dispersive X-ray analysis and transmission electron microscope techniques. The electrocatalytic activity of Pt/C catalysts toward HOR and ORR was examined by cyclic voltammetry (CV) on a rotating ring-disk electrode (RRDE) and compared with E-Tek Pt/C. The ORR was predominantly involved via four-electron process with the first electron transfer being the rate-determining step. However, the specific activity and mass activity were greatly influenced by the pre-treatment employed.     

自组装制备铁质文物保护用纳米缓蚀颗粒

长效缓蚀材料对于铁质文物的长期保护有着至关重要的作用.通过层层自组装的方法,在带负电荷的SiO2胶粒表面交替组装上了带正电荷的聚乙烯亚胺(PEI)层,带负电荷的聚苯乙烯磺酸钠(PSS)层,以及带正电荷的缓蚀活性成分苯并三氮唑(BTA)层.利用透射电子显微镜、zeta电位仪、X射线光电子能谱仪(XPS)等对纳米缓蚀颗粒进行了表征.结果表明,随着组装过程的进行,胶体粒子尺寸依次增大,颗粒表面zeta电位出现负正交替变化,表面元素化学环境也随之改变,氮原子的结合能随静电作用的增强向高位移动.缓蚀剂的负载量可通过多层组装方式提高,BTA单层负载量可达到35.4mg/g SiO2.     

活性屏离子氮化机理的研究

在真空室内放置一个铁制的网状圆筒 ,并与直流高压电的负极相接 ,在直流电场的作用下 ,通过气体离子对圆筒的轰击溅射 ,产生了一些纳米数量级的活性粒子 ,利用这些高活性的纳米粒子簇可以对放置在圆筒内钢的表面进行氮化处理。实验证明 ,这些活性粒子是中性的Fe4N粒子 ,所以被处理的工件既可以处于悬浮电位 ,也可以处于零电位。活性屏离子氮化可以获得和普通直流离子氮化同样的处理效果 ,并解决了离子氮化技术的不足。     

纳米粒子作为润滑油脂添加剂的研究进展

纳米粒子作为润滑油脂添加剂以改善润滑油脂的润滑特性是纳米润滑技术的前景之一,它将深刻影响国民经济未来的发展.由纳米特征带来的性能变化,将使我国国产功能部件的整体性能产生质的飞跃,纳米粒子作为润滑脂添加剂适用于功能部件性能的优化和改良,能普遍地、根本性地提高功能部件的一致性、耐久性、可靠性,且纳米粒子作为润滑油脂添加剂价格低廉,非常适合国产部件的普及化运用.利用纳米润滑技术弥补我国在精密制造方面的不足,将为纳米润滑技术在功能部件中的大规模应用提供可能.     

纳米材料对超高性能混凝土动态力学特性的影响实验研究

对掺入不同种类和含量纳米材料的超高性能混凝土分别进行了静、动态压缩和劈裂试验,分析了纳米材料种类及其含量对超高性能混凝土材料动态力学特性的影响,给出了超高性能混凝土动态增长因子曲线.结果表明:超高性能混凝土为应变率敏感性材料,超高性能混凝土的动态强度随着应变率的增大而增强;纳米材料种类对超高性能混凝土动态强度的影响不明显,但对其动态增长因子影响比较显著;纳米材料含量对超高性能混凝土动态强度和动态增长因子影响明显,适宜的掺量能够更有效地改善超高性能混凝土的动态力学性能.     

聚合物纳米复合材料结晶行为研究进展

综述了聚合物/粘土纳米复合材料及聚合物/刚性纳米粒子复合材料中基体树脂的结晶行为,并分析了纳米粒子影响聚合物结晶过程的机理。     

涤纶织物不同纳米颗粒化学复合镀铜性能分析

使用吐温80分别分散纳米ZnO,Si3N4,Fe3O4,ZrC和SiO2颗粒,然后将其添加到化学镀铜液中对涤纶织物进行不同纳米颗粒化学复合镀铜,借助扫描电镜、X射线能谱议、X射线衍射仪和热重分析仪对镀层表面形貌、成分、结构和纤维热性能进行了研究,测定了化学镀铜织物的电磁波屏蔽、导电和耐磨性能。结果表明,与普通化学镀铜织物相比,不同纳米颗粒复合镀铜织物镀层表面粗糙度有所增加,孔隙率明显减少,镀层结构和热起始分解温度变化不明显,晶粒尺寸有所改变。当纳米颗粒添加量不大时,对电磁波屏蔽效能和表面比电阻影响不大,而耐磨性变差。随着增重率的增加,纳米颗粒复合镀铜织物的电磁波屏蔽效能开始时增加较快,后趋于缓慢。     

聚合物分散剂对纳米四氧化三钴制备的影响

在均匀沉淀法制备纳米Co3O4的过程中,研究了加入聚乙二醇(PEG-600,PEG-1000)和低相对分子质量的聚丙烯酸钠(PAANa)作为分散剂对前驱体和产物的影响。研究结果表明:加入聚合物分散剂后,能有效地防止纳米粒子的团聚,并能通过聚合物分散剂的相对分子质量来控制产物粒子的形状和大小;当PEG-1000的用量为40mg/mL时,可以获得平均粒径为20nm左右的球形Co3O4;当PAANa用量在15mg/mL左右时,可得到粒径