ELECTROCATALYSTS BASED ON MONO/PLURIMETALLIC CARBON NITRIDES FOR POLYMER ELECTROLYTE MEMBRANE FUEL CELLS FUELLED WITH HYDROGEN (PEFC) AND METHANOL (DMFC) AND FOR H2 ELECTROGENERATORS

摘要

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. The second step consists of the thermal treatments to decompose the precursors in an inert atmosphere leading to the production of the carbon nitrides. In the last step the chemical and electro-chemical activation of the electrocatalysts is performed. Precursors are obtained through reactions leading to: a) the complexation of a “soft” transition metal with a coordination complex acting as a ligand to obtain clusters; b) 3-D networking of the resulting clusters through suitable organic molecules and/or macromolecules.