Solvothermal Reduction of Graphite Oxide Using Alcohols

In the present work, we use either ethanol or ethylene glycol as reducing agents through the solvothermal method for graphite oxide reduction. A sulfuric acid treatment before the reduction process was also applied to evaluate its influence on the epoxy group ring-opening reaction. Reduced graphene oxide (RGO) samples were obtained with morphology like crumpled sheets. X-ray diffraction analyses (XRD) showed that the RGO produced via ethylene glycol (EG) reduction followed by treatment with sulfuric acid (RGOEGH) presented the largest d-spacing (0.4114 nm). For reduction with ethanol (RGOEt), the d-spacing value was 0.3883 nm. Infrared spectroscopy (FTIR) results indicated that RGOEt exhibited very low-intensity bands related to oxygenated functional groups, suggesting a high reduction degree, while the sample reduced with EG contained oxygen group bands in the spectrum that disappeared when H2SO4 pretreatment was performed. Thermal gravimetric analyses (TGA) results showed that the samples present high stability and confirmed the reduction process. Moreover, the synthesized RGO sheets were comparable to those produced via more expensive and toxic methodologies.

本研究通过溶剂热法，选用乙醇或乙二醇作为还原剂，用于氧化石墨的还原制备。同时在还原工序前增设硫酸预处理步骤，以探究其对环氧基团开环反应的影响。所制备的还原氧化石墨烯（RGO）样品形貌均呈褶皱片状。X射线衍射分析（XRD）结果显示，经乙二醇（EG）还原并经硫酸预处理的RGO样品（记为RGOEGH）具有最大的层间距（0.4114 nm）；而以乙醇还原的RGO样品（记为RGOEt）的层间距为0.3883 nm。傅里叶变换红外光谱（FTIR）测试结果表明，RGOEt的含氧官能团特征峰强度极低，说明其还原程度较高；而乙二醇还原所得样品的含氧官能团峰在经硫酸预处理后完全消失。热重分析（TGA）结果显示，所有样品均具有较高的热稳定性，验证了还原反应的成功进行。此外，本研究合成的RGO片层性能可媲美那些成本高昂且毒性较强的传统方法制备的产品。