The invention describes the preparation of electrocatalysts, both anodic (aimed at the oxidation of the fuel) and cathodic (aimed at the reduction of the oxygen), based on mono- and plurimetallic carbon nitrides to be used in PEFC (Polymer electrolyte membrane fuel cells), DMFC (Direct methanol fuel cells) and H2 electrogenerators. The target of the invention is to obtain materials featuring a controlled metal composition based on carbon nitride clusters or on carbon nitride clusters supported on oxide-based ceramic materials. The preparation protocol consists of three steps. In the first the precursor is obtained through reactions of the type: a) sol-gel; b) gel-plastic; c) coagulation-flocculation-precipitation.