Efficient and cost-effective ORR electrocatalysts based on low content transition metals highly dispersed on C3N4/super-activated carbon composites

Oxygen reduction reaction (ORR) is one of the most important electrochemical reactions for fuel cells. However, commercial Pt-based catalysts used have important limitations such as their deactivation by carbon monoxide and Pt scarcity. In the present work, small and highly-dispersed copper and iron clusters were anchored onto composite supports based on carbon nitride (C3N4) nanostructures and a highly porous carbon material. Catalysts with a moderate carbon nitride content showed an interesting catalytic behaviour because of the combination of the metallic active sites and the availability of micropores, which play an active role in ORR. The presence of either Fe or Cu in the synthesis affected the structure of the resulting composite materials, as well as their electrocatalytic activity. Copper-based materials showed superior catalytic activity, which is supported by the information obtained from the evaluation of the system using DFT computational calculations.