摘要
采用混合的浓硝酸和浓硫酸处理石墨层排布为鱼骨类和平行类的碳纳米纤维，分别用X-射线衍射、电子显微镜和N2-物理吸附研究了氧化处理对碳纳米纤维石墨层结构和织构性质的影响；利用FT—IR、酸碱滴定和热重分析对碳纳米纤维表面引入的舍氧基团进行了研究。结果表明，经过氧化处理的碳纳米纤维仍然保持类石墨结构。但织构性质在激烈的氧化条件下发生显著的改变。氧化处理在碳纳米纤维表面引入了大量的羧基基团，并且随着氧化处理温度的升高表面引入的羧基基团密度增大。在相同的氧化条件下，鱼骨类碳纤维表面生成的羧基基团的量明显高于平行类碳纳米纤维。以氧气为氧化剂，在没有溶剂的情况下，碳纳米纤维负载的Pd催化剂在基甲醇氧化反应中具有很高的活性，并且碳纳米纤维表面的羧基基团对其负载的Pd催化剂活性有明显的促进作用。
Two types of carbon nanofibres were treated with a mixture of concentrated nitric and sulphuric acid in an autoclave at different temperatures. The effects of oxidation treatment on the graphite structure, texture,and surface properties of carbon nanofibres were studied by means of XRD,TEM,Nz--physisorption, TG, and acid- base titrations. The results demonstrate that the graphite--like structure of carbon nanofiber is maintained after treatment in mixed acid,but the texture properties are changed severely in serious oxidation condition. The concentrations of the formed carboxylic groups on the surface of carbon nanofibres increase with the treatment temperatures. In addition, The concentration of the carboxylic groups on the surface of the fishbone type carbon nanofibres is higher than that of the parallel type carbon nanofibres at the same treatment temperature. Interestingly,carboxylic--functionalized carbon nanofiber-- supported Pd catalysts show a good performance for oxidation of benzyl alcohol with molecular oxygen. Furthermore,the carboxylic species on carbon nanofiber--supported Pd catalysts play an important role in the promotion of catalytic activity.
出处
《炭素》
2009年第4期9-15,共7页
Carbon
基金
温州市科技计划项目（G20080144）资助
关键词
碳纳米纤维
氧化处理
织构性质
表面性质
负载钯催化剂
carbon nanofibers
oxidation treatment
texture properties
surface properties, supported Pd catalys
