Synthesis and Electrochemical Characterization of Co, Cu, Fe, Ni and Mn-based Catalysts for ORR in PEM Fuel Cells

摘要

We have synthesized a variety of transition metal-ligand complexes supported on carbon black to be used as catalysts for PEMFC cathode electrodes. Complexes of Cu, Co, Fe, Ni and Mn with ligands such as diaminotriazole (DATZ), triazolephthalocyanine-type molecules (TrPc), and pyridine were either adsorbed or covalently attached via diazonium coupling to BP2000 carbon support. Electrochemical activity was investigated via rotating ring disk electrode experiments (RRDE). The as-prepared materials showed low catalytic activity towards the oxygen reduction reaction (ORR). All of our samples demonstrated improved catalytic activity after pyrolysis in an inert atmosphere at temperatures above 600 ℃. In general, adsorbed complexes showed lower catalytic activity than immobilized ones. In addition, complexes using TrPc-type ligand presented higher catalytic activity and current densities than DATZ based materials. Catalysts using Co and Cu as the metal centers showed the best onset potentials after the heat treatment.