Carbon Nanodots as Feedstock for a Uniform Hematite-Graphene Nanocomposite

High degrees of dispersion are a prerequisite for functional composite materials for applications in electronics such as sensors, charge and data storage, and catalysis. The use of small precursor materials can be a decisive factor in achieving a high degree of dispersion. In this study, carbon nanodots are used to fabricate a homogeneous, finely dispersed Fe₂O₃-graphene composite aerogel in a one-step conversion process from a precursor mixture. The laser-assisted conversion of small size carbon nanodots enables a uniform distribution of 6.5 nm Fe₂O₃ nanoparticles during the formation of a highly conductive carbon matrix. Structural and electrochemical characterization shows that the features of both material entities are maintained and successfully integrated. The presence of Fe₂O₃ nanoparticles has a positive effect on the active surface area of the carbon aerogel and thus on the capacitance of the material. This is demonstrated by testing the performance of the composite in supercapacitors. Faradaic reactions are exploited in an aqueous electrolyte through the high accessible surface of the incorporated small Fe₂O₃ nanoparticles boosting the specific capacitance of the 3D turbostratic graphene network significantly.