▎ 摘　　要

Graphene quantum dots (GQDs) have a wide range of applications in energy, optoelectronics, and bio-nanotechnology. However, their high cost is a barrier for commercial application. Here, we report a cost-effective ball-milling method for producing GQDs using a mixture of carbon nanocapsules (20 nm) as the carbon source and sodium carbonate as the intercalation agent. The results show that the proposed exfoliation method produces GQDs with diameters of 1.0-4.0 nm and a very small amount of grafted functional groups that exhibit blue light emission under ultraviolet irradiation. The quantum yield is about 5%. The proposed method has great potential for the production of GQDs using low-cost raw materials.