▎ 摘　　要

The application of bioelectrochemical system (BES) for recalcitrant contaminant removal is a promising strategy for wastewater treatment but is limited to the low cathodic reduction efficiency. In this paper, a new approach using polypyrrole as nitrogen source has been utilized for the fabrication of nitrogen-doping graphene (NG) modified graphite felt (GF) electrodes. The results of the Raman spectrum and X-ray photoelectron spectroscopy confirmed that the nitrogen species, i.e., pyridinic N, pyrrolic N and graphitic N, in the NG sheets could be conveniently controlled by tuning the pyrolysis temperature from 300 to 600 degrees C during carbonization process. Cyclic voltammetry and electrochemical impedance spectra measurements verified that the catalytic activity and electron transfer efficiency of the 'as prepared' electrodes were greatly improved. Due to the synergistic effect of pyrrolic N and graphitic N, the 4-nitrophenol reduction efficiency of the modified cathode increased 2.1 times higher than that of blank GF cathode in the BES system.