硝酸钴催化热解沥青制备碳纳米管

Synthesis of Carbon Nanotubes Via Co-Catalyzed Pyrolysis of Pitch

以硝酸钴为催化剂、聚乙烯吡咯烷酮(PVP)为保护剂,采用催化热解沥青的方法制备了碳纳米管(CNTs)。研究了热处理温度和催化剂含量对沥青热解后的残碳率、石墨化度及CNTs的生长情况的影响。采用X射线衍射(XRD)及场发射扫描电子显微镜(FE-SEM)对所合成CNTs的相组成、显微结构和生长情况进行了表征。结果表明:(1)催化剂的加入有利于固定沥青热解产生的含碳气体,沥青裂解后的最高残碳率可达69%;相比之下,无催化剂时,试样的残碳率仅为50%左右;(2)催化剂的加入可以降低沥青的石墨化温度,其石墨化度随热处理温度的升高而增大;(3)催化剂的加入还可以促进CNTs的原位生成,实验条件下其最佳用量为0.25wt.%。

Carbon nanotubes（CNTs） were prepared through catalytic pyrolysis of pitch using cobalt nitrate as the catalyst precursor and polyvinyl pyrrolidone（PVP） as protective agent. The influence of reaction temperature and catalyst content on the carbon yield and graphitization degree of pitch and synthesis of CNTs was investigated. The structure and morphology of pyrolyzed pitch were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results show that the addition of catalyst is beneficial to fix the carbonaceous gas releasing from the pyrolyzed pitch, and the highest ratio of carbon yield of 69% was obtained for the sample with cobalt nitrate as catalysts. For comparison, carbon yield of only 50% was got for the sample without any catalyst. The addition of catalyst can also reduce the graphitization temperature of pitch and promote the synthesis of CNTs, the graphitization degree increased with the heat treatment temperature increasing, and the optimal content of catalyst is 0.25 wt.% in present paper.