raphene has attracted great interests due to their unique physical and chemical properties, which could be utilized for numerous potential applications. To improve the graphene functionality, controllable doping represents an effective way to modulate the electronic properties. Nitrogen (N) doping has been frequently used to approach the n-type behavior and to enhance the conductivity of grapheme. In N-doping processes, it is significant to identify the doping species, which have a great influence on the electronic structure of graphene. The team probed the evolution of the solid state N-doping in graphene utilizing the X-ray absorption near-edge structure (XANES) spectroscopy (Fig. 1). The XANES spectra at C, N and O K-edges showed that the doped N species were urea attachments to graphene at annealing temperatures lower than 300 ºC, while a transition from urea to amino species was observed at 400 ºC. At higher temperatures, pyridinic and graphitic types dominated the doping. The results indicated that XANES was a powerful tool to monitor the electronic structure of graphene-based materials. This work was published in Carbon (2012).

　　　　　　　　　　　 
Fig. 1 C and N K-edge XANES spectra of GO, GRA-200, GRA-300, GRA-400, GRA-500 and GRA-600.

Article：

Jun Zhong, Jiu-Jun Deng, Bao-Hua Mao, Tian Xie, Xu-Hui Sun, Zhi-Gang Mou, Cai-Hao Hong, Ping Yang, Sui-Dong Wang*, Probing solid state N-doping in graphene by X-ray absorptionnear-edge structure spectroscopy, Carbon 50, 321-341, 2012.