Buffering agents-assisted synthesis of nitrogen-doped graphene with oxygen-rich functional groups for enhanced electrochemical performance

Designed growth of two types of N-doped graphene nanosheets has been realized in a mild hydrothermal process using NH4H2PO4 and (NH4)2HPO4 as buffering agents which make different contribution to the morphology, doping concentration and electrochemical performance of the functionalized graphene. The graphene nanosheets grown using NH4H2PO4 (NGC) have less nitrogen content but more oxygen than those using (NH4)2HPO4 (NGL). The specific capacitance of NGC is higher than that of NGL at all investigated current densities while the capacitance attenuation of NGL shows better durability than that of NGC, which can be ascribed to different synergistic contribution of N- and O- groups.246