Microwave synthesis of carbon onions in fractal aggregates using heavy oil as a precursor
Microwave synthesis of carbon onions in fractal aggregates using heavy oil as a precursor
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DOI：
10.1016/j.carbon.2018.07.066
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发表时间：
2018-11-01
期刊：
影响因子：
10.9
通讯作者：
Rigby, Sean P.
中科院分区：
文献类型：
--
作者：
Adam, Mohamed;Hart, Abarasi;Rigby, Sean P.
在这项工作中，我们报告了一种通过微波加热重油制备碳洋葱的方法。结果表明，在300 W下微波加热重油与碳催化剂的混合物导致几厘米长的分形碳结构的生长在短短60 s。扫描电子显微镜（SEM）图像显示，该结构主要由直径从几十到几百纳米的小颗粒网络组成。高分辨率透射电子显微镜（HRTEM）图像显示存在无序的石墨结构，包括直径小至30 nm的碳洋葱。这是支持的拉曼光谱，显示了典型的光谱碳洋葱无序石墨结构。CO2气体吸附结果表明，比表面积高达164 m2/g。碳洋葱被认为是通过将油热解成轻质烃，然后同心石墨层的成核和生长而形成的。碳树，随后，增长通过聚集的碳洋葱和热解碳的进一步沉积，与电场配置有利于细分支的纵向生长。这项研究表明，碳洋葱可以从廉价的未经精制的液体前体制备。(C)2018作者爱思唯尔有限公司出版
In this work we report a method for preparing carbon onions through microwave heating of heavy oil. It was shown that microwave heating of heavy oil mixed with a carbon catalyst at 300W leads to the growth of a several-centimetre long fractal carbon structure in just 60 s. Scanning electron microscopy (SEM) images showed that the structure is predominantly made of networks of small particles with diameters ranging from tens to hundreds of nanometres. High-resolution transmission electron microscopy (HRTEM) images revealed the presence of disordered graphitic structures, including carbon onions with diameters as small as 30 nm. This was supported by the Raman spectroscopy which showed typical spectra for carbon onions with disordered graphitic structure. CO2 gas sorption results revealed a specific surface area of up to 164 m(2)/g. The carbon onions are believed to form through pyrolysis of the oil into light hydrocarbons followed by nucleation and growth of concentric graphitic layers. The carbon tree, subsequently, grew through aggregation of the carbon onions and further deposition of pyrolytic carbon, with the electric field configuration favoured the longitudinal growth of thin branches. This study demonstrates that carbon onions can be prepared from cheap unrefined liquid precursors. (C) 2018 The Authors. Published by Elsevier Ltd.