催化剂的合成方法及配比对CVD法制备碳纳米管的影响

Effects of the preparing method and quota of the catalyst on the synthesis of carbon nanotubes using CVD method

用离子注入法、简单混合法和水热晶化法分别制备了片状负载型系列、粉状混合型系列及粉状负载型系列催化剂.用3种系列催化剂通过CVD法分别制备了碳纳米管粗产物,用TEM和SEM检测手段对粗产物形貌进行了观察.结果表明,片状负载型催化剂:当Fe(Ⅱ)离子注入能量为25keV、剂量为1×1016cm-2时其催化活性较高,制得的碳纳米管含量较多,管径均匀(约20nm),但粗产物数量少;粉状混合型催化剂(Co/石墨):当纳米Co粉比例为15%时具有一定的催化活性,CVD法制备碳管有少量管径不一的碳管生成;水热法合成的粉状负载型催化剂(NiO/SiO2)分散性好、催化活性高,当硅 镍比为1∶12时制备的碳纳米管含量高,管径细而均匀(10～16nm),并且粗产物数量较多.

The sheet supported catalyst,pulverous mixed catalyst and pulverous supported catalyst were prepared separately by using ion injecting method,simple mixing method and hydrothemal method continuously used to synthesize carbon nanotubes(CNTs) by CVD.The morphology of carbon nanotubes was observed by using TEM and SEM.The results show that for sheet supported catalyst,the best activity condition is 25 keV Fe ion injecting energy,1×10^(16) cm^(-2) Fe(Ⅱ)ion , equable diameter (about 20 nm) original carbon nanotubes output can be got from it by using CVD method, and it had got more carbon nanotubes content but fewer yield; pulverous mixed catalyzer (Co/graphite) of 15% Co had a little activity,so can only be synthesized little different tube diameter carbon nanotubes. Pulverous supported catalyst (NiO/SiO2) synthesized by the hydrothermal method,when Si-Ni is (1∶12),have better dispersion and stronger catalytic activities,so that the pure CNTs with smaller tube diameters of 10～16 nm can be obtained at a high yield.