Figure 3.

An XPS measurement and peak assignment of nitrogen-doped graphene prepared by chemical vapor deposition. (a–c) N 1s and C 1s spectra of N-graphene freshly prepared on nickel, intercalated by gold, and treated by post-annealing. Note the large shifts caused by interaction with the substrate in the non-intercalated spectrum. The N 1s spectra shown in (b) have been background-subtracted. In the post-annealed sample, a peak at 401.3 eV was assigned to graphitic nitrogen, and another at 398.4 eV to pyridinic N. (d) Some proposed possible configurations of graphene nitrogen impurities: (1) graphitic (substitutional) N; three varieties of pyridinic bonding: (2) edge pyridinic N, (3) single N pyridinic vacancy (1NV), and (4) triple N pyridinic vacancy (3NV); (5) pyrrole-like N, (6) interstitial N or adatom, and (7) amine or (8) nitrile groups. Adapted with permission from [127], copyright 2011 The American Chemical Society.