N-doped mesoporous FeNx/carbon as ORR and OER bifunctional electrocatalyst for rechargeable zinc-air batteries

The development of low-cost bifunctional catalysts with high catalytic activity and durability for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a critical step for successful commercialization of Zn-air batteries. In this study, N-doped mesoporous carbon containing dispersed FeN x species is prepared and tested as an ORR and OER bifunctional catalyst for this battery type. Physical-chemical characterization of the newly prepared material demonstrated that NaCl can be effective as a porous structure forming template during carbonization . Resulting mesoporous structure containing FeN x species provides significant number of ORR and OER active sites. The optimized catalyst displays higher limiting current density and more positive half-wave potential for ORR than commercial Pt/C, as well as lower overpotential for OER than RuO 2 in KOH electrolyte. Furthermore, the obtained carbon material used as an air cathode in a specially assembled rechargeable Zn-air cell demonstrates electrocatalytic performance superior to those of Pt/C and RuO 2 electrodes, which makes it a promising non-precious metal bifunctional catalyst for Zn-air batteries.