Hollow yolk-shell nanoboxes assembled by Fe-doped Mn3O4 nanosheets for high-efficiency electrocatalytic oxygen reduction in Zn-Air battery

The rational design of cost-effective and highly-performance transition metal-based electrocatalysts towards oxygen reduction reaction (ORR) is essentially desirable to realize the commercial applications of metal-air batteries and fuel cells. Herein, Fe-doped Mn3O4 hollow yolk-shell nanoboxes (Fe-Mn3O4 HYSNBs) assembled from ultrathin nanosheets with a thickness of 1.5 nm are fabricated via utilizing KMn[Fe(CN)6] prussian blue analogs as the sacrificed precursor. Choreographed construction of such hybrid hierarchical architecture and composite is responsible to generate substantially active sites and abundant channels for mass diffusion and ion transport. The resultant Fe-Mn3O4 HYSNBs exhibit outstanding electrocatalytic activity and long-term stability, as well as good tolerance to methanol towards ORR in alkaline solution. Theoretical calculation demonstrates that the highly dispersed Fe active sites implanted within ultrathin Mn3O4 nanosheets can effectively regulate electronic structure and ORR intermediates adsorption energy. Moreover, Fe-Mn3O4 HYSNBs display high power density and specific capacity as an air–cathode in Zn-Air batteries, demonstrating outstanding practicability.