微波固相剥离制备石墨烯及其纳米流体的稳定性

Preparation of Graphene by Microwave-assisted Solid-state Exfoliation and Stability of Graphene Based Nanofluids

利用简便快捷的微波固相剥离法将氧化石墨烯(Graphene oxide,GO)剥离成石墨烯(Microwave reduced graphene oxide,MRGO),并将得到的石墨烯通过超声分散于不同的基液中。采用X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、拉曼光谱(Raman)、透射电镜(TEM)和紫外-可见光谱(UV-vis)对制备的样品进行了表征,发现通过这种方法可以使氧化石墨烯上的大部分含氧官能团得到去除。采用UV-vis,Zeta电位和沉淀物照片捕捉研究了pH值、超声时间和基液对石墨烯纳米流体稳定性的影响,发现经超声粉碎30min的石墨烯纳米流体能够保持均匀稳定达到一个月。此外,还分析了不同质量分数石墨烯-H2O纳米流体在不同温度下的导热系数,结果表明:石墨烯-H2O纳米流体的导热系数随着温度的升高和浓度的增大而提高,60℃时,质量分数为0.1%的石墨烯-H2O纳米流体的导热系数相对于基液提高了64%。

Graphene was prepared through a facile and fast method in which microwave-assisted solidstate exfoliation of graphene oxide（GO）was employed.Then the as-prepared graphene was dispersed in various base fluids by ultrasonication.X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）,Raman spectroscopy（Raman）,transmission electron microscope（TEM）and ultraviolet visible spectrometer（UV-vis）were used to characterize the samples.It is revealed that the majority oxygen-containing functional groups were removed from GO with this method.Influence of pH value,ultrasonication time and base fluid on stability of graphene based nanofluids were also investigated via UV-vis,Zeta potential and sediment photograph capturing.Graphene based nanofluids ultrasonicated for 30 min showed a good stability for 1 month.Besides,thermal conductivity of graphene-H2 O nanofluids with varying weight fractions at different temperatures was analyzed.The results showed that thermal conductivity of graphene-H2 O nanofluids enhances with the increase of temperature and weight fraction and thermal conductivity of graphene-H2 O nanofluids with the weight fraction of 0.1%at 60℃improves by 64%compared with that of the base fluid.