Continuous preparation of carbon nano-onions in a non-thermal plasma process

A novel non-thermal plasma process based on magnetically stabilized gliding arc discharge (MSGAD) is developed for continuous synthesis of carbon nano-onions (CNOs). CNOs with a diameter range of 70–200 nm are continuously prepared by propane decomposition. Results indicate that with increased residence time in the plasma region, the product morphology gradually changes from graphene nanoflakes (GNFs) to CNOs. It is proposed that CNOs synthesis mainly includes three stages: formation of GNFs, curving and closure of multiple GNFs, further graphitization. In addition, H2 content has a key role in CNOs formation since hydrogen has a significant effect on the formation and morphology of GNFs.