热处理条件对氧化石墨结构和导电性能的影响

氧化石墨是石墨的氧化产物．由于它的碳层表面引入了很多极性功能团，使得很多分子都能够嵌入其层间形成纳米复合物，但也正是这些功能团使得它散失了石墨良好的导电性。为了考察氧化石墨受热处理后还原的可能性，通过X-射线衍射、扫描电镜、红外光谱分析以及元素分析等手段研究了氧化石墨在不同热处理条件下的结构变化。研究发现热处理时的升温速度对氧化石墨的结构影响很大，快速升温时，氧化石墨迅速分解，发生膨胀形成类似于膨胀石墨的含有丰富的50nm至5μm左右孔洞的一种结构；而当缓慢升温时，氧化石墨随着热处理温度的升高，逐渐恢复成类似于石墨的结构，同时电导率也随热处理温度的升高而提高，当热处理温度高于180℃时，电导率大于1S／cm。这些结果表明利用氧化石墨作为前驱体，通过先制备聚合物／氧化石墨纳米复合物后经热处理来得到导电性的聚合物／碳纳米复合材料是可行的。

The influence of thermal treatment conditions on the structures and electrical conductivities of graphite oxide

Graphite oxide (GO) is an oxidation product of graphite. Due to the embedding of the functional groups in the carbon layers, GO exhibits rich intercalation chemistry but also loses the good electrical conductivity of graphite. To investigate the possibility of reducing GO by thermal treatment, the variation of the structures of the GO with the heat treatment conditions were studied by XRD, SEM, IR spectroscopy and elemental analysis. It is found that heating rate plays an important role in the structure of the thermal treated GO. When subjected to rapid heating, GO was decomposed into a very light soot containing many pores of different sizes in the range of 50 nm to 5 μm. When subjected to slow heating, GO tended to return to the graphene structure. The higher the thermal treatment temperature, the closer the crystal structure of the pyrolyzed GO is to that of the graphite and the higher the electrical conductivity of the pyrolyzed GO. The fact that the electrical conductivity of GO can be higher than 1 S/cm when it is treated at a temperature higher than 180 ℃ suggesting that it is possible to use GO as a precursor to make conducting polymer/carbon nanocomposites.