表面修饰型铂基氧还原电催化剂研究进展

氧气还原反应是燃料电池中的重要电极反应,但其动力学过程非常迟缓,需高度依赖资源稀缺、价格高昂的贵金属Pt.加之Pt基催化剂还面临着实际工况下耐久性不足的问题,这些都严重阻碍了燃料电池的产业化进程.对Pt基纳米催化剂进行表面功能化修饰可有效优化和提升其氧还原活性和稳定性.本文综述了最近几年表面修饰型Pt基氧还原催化剂的最...     

降解裙带菜多糖对纳米硒的形成与稳定作用

在常温下的降解裙带菜多糖(Degraded Undaria Pinnatifida Charv. Suringer polysaccharide, DUP)水溶液中, 由适当过量的抗坏血酸(Vc)与二氧化硒(SeO2)反应制备纳米单质硒(Se0). 通过共振瑞利散射、激光散射和透射电镜(TEM)研究了DUP对Se0粒径的调控和在液相中的稳定作用. 结果表明, DUP通过控制还原速度和表面修饰而把Se0粒子调节在较窄的粒径分布范围内当Se0浓度为0.0507—3.245 mmol/L时, DUP表面修饰的球状纳米硒的平均粒径稳定地保持在24—65 nm范围内, 4 ℃时可在水溶液中稳定保存1个月.     

表面改性SiO2对SSBR/BR绿色轮胎胎面胶结构与性能的影响

采用4种含不同官能基团修饰剂改性的二氧化硅SiO₂增强溶聚丁苯橡胶(SSBR)/顺丁橡胶(BR)共混体系, 制备了SSBR/BR/SiO₂橡胶纳米复合材料, 研究了其结构与性能. 结果表明, 在混炼胶体系中, 与未改性SiO₂填充的SSBR/BR相比, 改性SiO₂填充的SSBR/BR门尼黏度及结合橡胶含量显著增大, 表明填料-橡胶相互作用显著提高; 硫化焦烧时间缩短60%, 硫化速度增大了35%~40%. 在硫化胶体系中改性SiO₂填充的SSBR/BR具有更大的交联密度, 填料分散性明显改善, 同时也表现出更为优异的物理机械性能, 100%和300%定伸模量提高47%以上, 旋转滚筒式磨耗机法(DIN)磨耗降低5%~12%, 生热降低了约7%~13%, 热空气老化性能提升4%~22%, 代表滚动阻力的tanδ在60 ℃降低8%~13%. 此外, 与SSBR/BR/1165MP硫化胶相比, 用90 mmol/kg氨基改性SiO₂填充的SSBR/BR硫化胶的抗湿滑性能提高6.9%, 表现出最优的综合性能. 填料的良好分散及填料与聚合物的相互作用增强对于提高SSBR/BR/SiO₂胎面胶综合力学性能具有重要意义.     

A roadmap of battery separator development: Past and future

The battery separator is one of the most essential components that highly affect the electrochemical stability and performance in lithium-ion batteries. In order to keep up with a nationwide trend and needs in the battery society, the role of battery separators starts to change from passive to active. Many efforts have been devoted to developing new types of battery separators by tailoring the separator chemistry. In this article, the overall characteristics of battery separators with different structures and compositions are reviewed. In addition, the research directions and prospects of separator engineering are suggested to provide a solid guideline for developing a safe and reliable battery system.