▎ 摘　　要

The evolution of solid state N-doping in graphene has been probed using X-ray absorption near-edge structure (XANES) spectroscopy. The XANES spectra show that the modification of graphene with N species can be achieved by urea attachment at annealing temperatures lower than 300 degrees C. A transition from urea to amino species is observed at 400 degrees C. At higher temperatures, pyridinic and graphitic type doping are achieved. The results indicate that the electronic structure of graphene can be controlled by solid state treatment, involving different N species depending on the annealing process. (C) 2011 Elsevier Ltd. All rights reserved.