Nitrogen-doped graphene was synthesized by a hydrothermal method using graphene oxide (GO) as the raw material, urea as the reducing agent and nitrogen as the dopant. The morphology, structure, composition and electrochemical properties of the samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorptiondesorption analysis, electrical conductivity and electrochemical tests. The results show that urea can effectively reduce GO and achieve nitrogen doping under the hydrothermal conditions. By adjusting the mass ratio of raw materials to dopants, the graphene with different nitrogen doping contents can be obtained; the nitrogen content range is from 5.28~6.08% (atomic fraction percentage).When the ratio of dopant to urea is 1:30, the nitrogen doping content reaches a maximum of 6.08%.The supercapacitor performance test shows that the nitrogen content prepared by the ratio of 6.08% is the best at 0.1 A·g-1. The specific capacitance is 95.2 F·g-1.
