Amorphous carbon nitride films prepared by magnetron Sputtering technique display, as-prepared, a moderate reactivity. When electrochemically activated, they acquire a quasi-metallic behavior. This behavior has been assessed both by EIS and by scanning electrochemical microscopy which showed that the Surface is shared between active and inactive sites. X-ray photoelectron spectroscopy analysis indicated that electrochemical activation is accompanied by a decrease of the number of superficial nitrogen atoms involved in C-Nsp 3 bonds. (c) 2005 Elsevier B.V. All rights reserved.