Platinum-free Air Cathode Catalysts for Fuel Cells

Abstract

Platinum-free air cathode catalysts were prepared by heat-treating transition metal hexacyanometallate precursors under an inert atmosphere. The catalytic activity for oxygen reduction was examined with the floating electrode and rotating ring-disk electrode techniques. Among several Pt-free catalysts based on 3d-transition elements, catalysts containing cobalt or copper with iron exhibited high activity toward oxygen reduction, and the catalyst containing copper and iron showed very low generation of hydrogen peroxide during oxygen reduction. A possibility of the cost-effective air cathode catalysts for fuel cells substituting for Pt-based catalysts is discussed therefrom.