Abstract:

Reduced graphene oxide (rGO) with tunable conductivity has great promise for potential applications in the fields of advanced structural-functional composites, new chemical materials and so on. In this research, environment-friendly hydrothermal method was applied to prepare rGO. The conductivity of the synthesized rGO can be controlled from 10^-4 to 1 S·cm^-1 by changing the hydrothermal reaction temperature and time. Various characterization techniques such as UV-vis, FT-IR, XPS, SEM, XRD, and Raman spectroscopy were used to analyze the composition and structure change of the rGO. The results showed that the oxygen contained functional groups on the rGO surface decomposed rapidly at ≥ 120℃, and the content of oxygen contained functional groups decreased drastically at ≥ 140℃. Meanwhile, the carbon sp2 region of the rGO was recovered gradually, which caused the conductivity increased to 1 S·cm^-1 and the interlayer spacing decreased from 8.2 Å to 3.6 Å. Compared with thermal reduction method, hydrothermal method avoids the aggregation and stacking of the rGO, which has great significance in large-scale production of the rGO with tunable conductivity.

Key words: reduced graphene oxide, dispersion, preparation, nanomaterials, microstructure, conductivity

摘要：

导电性可调控的还原氧化石墨烯（rGO）在结构功能材料和化工新材料等领域具有重要的应用前景。本文利用水热还原法实现了rGO的绿色制备，并通过调控反应温度和时间，获得了电导率可控的rGO产品，其电导率范围为10^-4～1 S·cm^-1。采用UV-vis、FT-IR、XPS、SEM、XRD和Raman等表征方法系统研究了rGO还原过程中结构与组成的变化。发现GO还原过程中，其含氧官能团于120℃时开始明显分解，高于140℃后含量显著降低，GO片层sp2区域逐渐恢复，电导率逐渐增大到1 S·cm^-1，同时层间距从8.2 Å减少到3.6 Å（1 Å=0.1 nm）。对比热还原法，水热法有效避免了rGO片层的堆叠，产物分散性较好，有望规模化制备导电性可控的rGO产品。本研究成果对rGO生产和应用具有重要意义。

关键词: 还原氧化石墨烯, 分散液, 制备, 纳米材料, 显微结构, 电导率