Rational\nDesign of\na Co/MnO-Embedded 2D Nitrogen-Doped\nCarbon/Carbon Nanotube Hybrid Catalyst for Efficient Oxygen Catalysis\nand High-Capacity Zn–Air Batteries

Bimetallic catalysts used as air\ncathodes for Zn–air\nbatteries\noffer improved activity and performance by tuning the electronic structure\nand interactions between metals. In particular, the fabrication of\nmetal/metal compound heterostructure-embedded carbon catalysts is\nrequired owing to their desired properties; however, this often requires\nmultistep-involved/complex synthesis conditions, hampering large-scale\nproduction. In this study, a Co/MnO-embedded nitrogen-doped carbon/carbon\nnanotube (CM-N:C) was developed by using a simple synthetic strategy\nthat involved heat-treating the intermediate platform of a Co-based\ntwo-dimensional zeolitic imidazolate framework (2D ZIF). The 2D leaf-like\nproducts from the ZIF led to the exposure of abundant active sites,\nand the unique carbon/carbon nanotube hybrid structure resulted in\nthe good durability of the developed catalysts. Moreover, owing to\nthe heterojunction interface, modulated electronic configuration,\nand favorable porous features, the designed catalyst (CM-N:C) exhibited\nsuperior oxygen evolution and oxygen reduction catalytic activities.\nFurthermore, Zn–air batteries loading these catalysts demonstrated\nexcellent performance, with an especially high specific capacity of\n841.26 mAh/g<sub>zn</sub> and energy efficiency of 58.8% at 5 mA/cm<sup>2</sup>. This study provides a perspective for the development of\nefficient electrocatalysts and air cathode materials for sustainable\nenergy conservation systems.