NiO-Fe2O3/carbon nanotubes composite as bifunctional electrocatalyst for rechargeable Zn-air batteries

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential to metal-air batteries and fuel cells. Highly efficient and low-cost electrocatalysts for oxygen reactions are in urgent demand. Herein, we synthesized materials through Fe2O3 and NiO depositing on carbon nanotubes (CNTs) by hydrothermal method, which can perform as efficient bifunctional electrocatalysts for the ORR and OER. These catalysts mainly contain macropores which can provide sufficient surface area for active sites. With metal oxides depositing on CNTs, it overcomes some drawbacks such as low conductivity and agglomeration of metal oxides. The catalysts show great electrocatalytic toward ORR and OER even comparing with commercial Pt-C/RuO2 catalysts. Through constructing an air battery and testing the performance of cycling, the stability of the catalyst can also be proved.