Hydrothermal Synthesis of Carbon Nano-Onions from Citric Acid
Song Sang1,2, Sheng Yang1, Aoping Guo1,2
1Department Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, 19-Xinjiekouwai Street, Haidian, Beijing, 100875, P. R. China.
Abstract:
Carbon nano-onions with concentric fullerene-like carbon shells were synthesized by hydrothermal carbonization of citric acids at 180 °C and formed through the intermediates of graphene quantum dots, graphitic nano-sheets and graphitic hollow polyhedrons. The graphene quantum dots were firstly formed by the dehydration of citric acids and then grew and stacked into graphitic nano-sheets, which curved into graphitic hollow polyhedrons due to the interface energy. The graphitic hollow polyhedrons eventually transformed into spherical carbon nano-onions with the lowest interface energy in the hydrothermal solution by disordering and rearrangement of the carbon shell.
