Formation of graphene flowers during high temperature activation of mesocarbon microbeads with KOH

Graphene flowers on porous activated carbon was successfully obtained by activation of mesocarbon microbeads (MCMB) with KOH at high temperature. By investigation of structure evolution with temperature from 800 to 1100 degrees C, it was found the coarse surface of activated carbon with cracks and small particles became to be graphene flowers when the activation temperature reached 1000 degrees C. The activated carbon with graphene flowers had high specific surface area value (1855 m(2)/g) and pore volume (1.18 cm(3)/g), which was ascribed to the chemical reactions, K intercalation and existence of graphene flowers. From the microstructural analysis, it was deduced that graphene flowers on the activated carbon was obtained from the high ordered layers in the small building units of MCMB, which processed the removal of disordered carbon, remaining the high ordered layers left under high temperature activation. (C) 2016 Elsevier Inc. All rights reserved.