(97f) Studies on Fe Based Non Noble Metal Catalysts for Oxygen Reduction Reaction

In the ongoing effort to make polymer electrolyte fuel cells commercially available, the use of non-noble metal catalysts instead of expensive platinum and platinum alloy catalysts has been explored. Several studies have shown that certain non-noble metals, such as Co and Fe, when complexed with nitrogen donors and heat treated at high temperatures show activity towards electro reduction of oxygen. Previous studies in this laboratory have been conducted to optimize Co catalysts. This study focuses on the development of Fe based catalysts for oxygen reduction reaction in an acidic medium. The rotating ring disk electrode (RRDE) method was used to obtain polarization curves for the developed catalyst in 0.5M H2SO4 saturated with oxygen. The effect of metal : nitrogen donor ratio, wt% of the metal loading and temperature on activity of the catalyst is studied. Fe based catalysts exhibit four electron reduction mechanism for oxygen reduction reactions. Also, the developed catalyst exhibits less than 100 mV higher overpotential in comparison with commercial Pt based catalysts.