| 초록 |
Graphene oxide (GO) is aqueous dispersible oxygenated graphene, which shows colloidal discotic liquid crystallinity. Many properties of GO based materials are limited by the small flake size of GO. Unfortunately, typical sonochemical exfoliation of GO from graphite generally leads to broad size and shape distribution. Here, we introduce a facile size selection of large size GO exploiting liquid crystallinity and investigate on the size dependent N-doping and oxygen reduction catalysis. In the biphasic GO dispersion that both isotropic and liquid crystalline phases are equilibrated, large size GO flakes are spontaneously concentrated within the liquid crystalline phase. N-doping and reduction of the size selected GO exhibits that N-dopant type is highly dependent on GO flake size. Large size GO demonstrates quaternary dominant N-doping and the lowest onset potential (-0.09 V) for oxygen reduction catalysis. |
