A variety of materials have been investigated for their catalytic properties in the ORR, including:
Platinum and platinum-based alloys: These are the most commonly used catalysts due to their high activity, but their high cost and scarcity limit widespread application. Transition metal oxides: These materials offer a cost-effective alternative, though they generally exhibit lower activity compared to platinum. Carbon-based materials: Recent advances in graphene and carbon nanotubes have shown promise for ORR catalysis due to their high surface area and electrical conductivity. Non-precious metal catalysts: Iron, cobalt, and nickel-based catalysts are being explored to reduce costs while maintaining reasonable catalytic activity.
