Fig. 3. (a) Ag MN, Ag 3d and Cl 2p signals for 1-NP. (b) Ag MN, Ag 3d and Br 3d signals for 2-NP. (c) Ag MN, Ag 3d and I 3d signals for 3-NP. The Ag MN signals were determined by AES, while the binding energies for Ag 3d, Cl 2p, Br 3d and I 3d were measured by XPS.