Synthesis of nitrogen doped graphene from graphene oxide within an ammonia flame for high performance supercapacitors

This paper introduces a novel process for preparing nitrogen (N) doped graphene by using an ammonia flame treatment under ambient conditions, which is simple, effective, faster and economical. That is, when graphene oxide (GO) was treated in the ammonia flame, GO not only could be reduced to graphene, but also could be doped with nitrogen atoms simultaneously. Furthermore, due to the special atmosphere in the ammonia flame, the N-doped graphene exhibited differences from the N-doped graphene by using other processes, which indicated the special properties and potential applications. The experimental results revealed: (1) the N atom concentration was up to 3.97 at% in the N-doped graphene; (2) various nitrogen species including pyridinic-N, pyrrolic-N and quaternary-N were detected in the N-doped graphene; (3) the specific capacitance of the N-doped graphene was 246.4 F g(-1) at a current density of 1 A g(-1) with high cycle stability, which was about 2 times higher than that of regular graphene without N-doping. It was indicated that this N-doped graphene could be an excellent electrode material for supercapacitor applications.