Preparation of few-layer and single-layer graphene by exfoliation of expandable graphite in supercritical N,N-dimethylformamide
Preparation of few-layer and single-layer graphene by exfoliation of expandable graphite in supercritical N,N-dimethylformamide
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超临界N,N-二甲基甲酰胺中可膨胀石墨剥离制备少层和单层石墨烯
DOI：
10.1016/j.supflu.2012.01.002
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发表时间：
2012-03-01
影响因子：
3.9
通讯作者：
Gao, Hanyang
中科院分区：
文献类型：
--
作者：
Liu, Changqing;Hu, Guoxin;Gao, Hanyang
在超临界N，N-二甲基甲酰胺（DMF）中，以可膨胀石墨（EG）为原料，在不到15分钟的时间内制备出了少层石墨烯（FG）。单层石墨烯是通过超临界DMF中FG的剥落制备的。采用原子力显微镜（AFM）、x射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）和拉曼光谱对样品进行了表征。AFM结果表明，石墨烯的平均厚度约为3 nm，单层石墨烯的平均厚度约为1.2 nm。Raman结果表明，FG的I-D/I-G为0.3，表明FG中存在少量缺陷。此外，我们还研究了工艺参数对FG收率的影响。结果表明，在最佳条件下（浓度为2 mg/ml，温度为673K，体积比为0.67），产率可达7 wt%。此外，FG的形成温度很低（473 K）。最后，这些结果表明EG是制备FG和单层石墨烯的优良前驱体。(C) 2012 Elsevier B.V.版权所有
Few-layer graphene (FG) is produced in supercritical N,N-dimethylformamide (DMF) using expandable graphite (EG) as starting material in less than 15 min. Monolayer graphene is produced by exfoliation of FG in supercritical DMF. The samples were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and Raman spectroscopy. AFM result reveals that the average thickness of FG is about 3 nm and monolayer graphene is about 1.2 nm. Raman result indicates that the I-D/I-G of FG is 0.3, which proves a small proportion of defects in it. Moreover, we have studied the effect of process parameters on the yield of FG. Results show that a yield of 7 wt% can be obtained at an optimum condition (with concentration being 2 mg/ml, temperature being 673K, and volume ratio being 0.67). Besides, the temperature of FG formation is very low (473 K). Finally, these results show that EG is an excellent precursor for the fabrication of FG and monolayer graphene. (C) 2012 Elsevier B.V. All rights reserved.