石墨烯-碳量子点复合材料的电化学性能研究

采用Hummers法和水热法,制备石墨烯和碳量子点溶液作为前驱体,然后通过一步煅烧法制得石墨烯-碳量子点复合材料。借助SEM、UV-Vis、FTIR等手段,对样品的形貌和结构进行表征;利用循环伏安法(CV)、差分脉冲伏安法(DPV)及恒流充放电循环测试等,重点考察了样品的电化学性能。结果表明,在石墨烯表面负载碳量子点可增加材料的比表面积并改善其机械性能,由于活性位点的增加,所制石墨烯-碳量子点复合电极具有较好的可逆性及电化学活性;在检测不同浓度双氧水时,复合电极的灵敏度为纯石墨烯电极的1.4倍左右;石墨烯-碳量子点复合材料作为锂离子电池负极使用时,与纯石墨烯材料相比具有更好的循环稳定性,且容量保持率提高了1.67倍。

Electrochemical performance of graphene/carbon quantum dots composites

The Hummers method and hydrothermal method were adopted to prepare graphene and carbon quantum dots solution respectively as the precursors, and then graphene/carbon quantum dots composite was synthesized by a one-step calcination approach. The mophology and microstructure of the prepared samples were characterized by means of SEM, UV-Vis and FTIR, and the electrochemical properties were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and constant current charge-discharge cycle test. The results show that the carbon quantum dots on the graphene surface can increase the specific surface area of the composite material and improve its mechanical property. Due to the increase of active sites numbers, the prepared composite electrode exhibits good reversibility and electrochemical activity; the sensitivity of the composite electrode is about 1.4 times that of the pure graphene electrode when detecting the H₂O₂ soluition with different concentrations. Moreover, the graphene/carbon quantum dot composite has a better cycle stabilitity campared with the pure graphene material when used as the negative electrode of lithium ion battary, and the capacity retention rate register a 1.67 times increase.