▎ 摘　　要

Nitrogen-doped graphene/Fe2O3 composites (NGFeCs) have been synthesized by a simple hydrothermal method. The structure and morphology of the samples were analyzed by X-ray diffraction, Raman spectra, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results indicate that Fe2O3 particles with size about 20-100 nm were homogenously anchored on nitrogen-doped graphene (NG) sheets. Electrochemical properties of the synthesized materials were characterized by serials of electrochemical measurements in 1 M Na2SO4 electrolyte. The as-prepared NGFeCs show a better electrochemical performance than the graphene/Fe2O3 composites (GFeCs). The specific capacitance of NGFeCs electrode is 260.1 F/g (150.4 F/g for GFeCs electrode) at a current density of 2 A/g. Additionally, over 82.5% (214.6 F/g) of the original capacitance is retained after 1000 cycles at a current density of 2 A/g (61.4% for GFeCs electrode). The superior electrochemical performance can be ascribed to the good electronic conductivity and more active and nucleation sites introduced by the nitrogen-doping (especially by pyrrolic N-doping). (C) 2014 Elsevier B.V. All rights reserved.