通过pH调控水热法石墨烯的电磁性能

pH dependent electromagnetic property of graphene prepared by hydro thermal method

采用缓冲溶液调节氧化石墨烯水分散液的pH,经过水热处理制备了石墨烯吸波剂。使用FESEM、XPS、Raman光谱、矢量网络分析等研究了溶液的pH为2、7和12时,石墨烯吸波剂的微观形貌和电磁性能的差异。结果表明,氧化石墨烯片层于不同pH的溶液中的聚集行为差异,使得相较于在中性和碱性溶液中,在经缓冲溶液维持的酸性溶液中制备的石墨烯吸波剂的片层较薄,褶皱和孔隙结构丰富,具有更高的介电常数与损耗能力。其中,应用缓冲溶液是得到较好性能的关键步骤。理论计算表明,pH为2时制备的石墨烯吸波剂在添加量仅为2.0%、厚度为10 mm时,对1~18 GHz电磁波的有效吸收频带宽度可达9.6 GHz。

A series of reduced graphene oxide(rGO)were prepared via hydro thermal reaction in which the pH values of the reactant solutions were respectively maintained at 2,7,and 12 with buffer solution.The microscopic morphology and electromagnetic properties of rGO were studied with FESEM,XPS,Raman spectroscopy and vector network analyzing.The results show that the pH value of solution has a significant impact on the microscopic morphology and electromagnetic parameters of the rGO products,due to the different aggregation behavior of GO sheets under corresponding conditions.The rGO prepared under acidic environment exhibits a characteristic of thinner layer and higher wrinkle density as well as higher dielectric constant and loss capability.Also,the use of buffer solution has a unique effect on the adjustment of the products’performance.The effective absorption bandwidth of rGO-pH2 sample with only 2.0%addition could reach 9.6 GHz at a thickness of 10 mm.