The simultaneous synthesis of carbon dots and carbon spheres with tunable sizes using a vertical chemical vapour deposition method

Herein we report on the direct synthesis of solid hydrophobic carbon dots (CDs) and simultaneously carbon spheres (CSs), using a vertical chemical vapour deposition (CVD) reactor. The HRTEM data indicated that the CDs and CSs originated from different carbon building blocks indicated that the CDs and CSs originated from different carbon building blocks. The CDs were obtained by reacting acetylene (C2H2) and Ar mixtures at high flow rates (>= 500 sccm) and high temperatures (800-1000 degrees C). TEM studies indicated that the CDs produced were graphene-like quantum dots that increased in size from c. 3 nm to 8 nm as the Ar flow rate (constant C2H2 flow rate) was decreased, while small solid CSs (c. 100 nm) were also synthesised in the process. The CSs had a typical spherical layered structure with no graphitic core. A mechanism to rationalise the observation that the CDs and CSs grew simultaneously by different pathways with no formation of intermediate-sized particles is given.

Automated summary

In this study, solid hydrophobic carbon dots and carbon spheres were synthesized directly using a vertical chemical vapour deposition reactor. The carbon dots and carbon spheres were found to originate from different carbon building blocks. The carbon dots were obtained through the reaction of acetylene and Ar mixtures at high flow rates and temperatures, while the carbon spheres were synthesized through a different pathway and had a typical spherical layered structure without a graphitic core.