Engineering VN/Co<sub>5.47</sub>N Nanostructures with\nInterfacial Electronic and Atomic Reorganization for Oxygen Reduction\nand Zn–Air Batteries

Interfacial\nelectronic and atomic structural reorganization in\nheterojunction hybrids will unlock great potential for achieving efficient\ncatalysis. Herein, VN/Co<sub>5.47</sub>N nanopolyhedrons were first\nprepared by ammonization of functional ZIF-67 with vanadate and further\nemployed as model catalysts to highlight the interfacial electronic\nand atomic synergistic effects on the oxygen reduction reaction (ORR).\nX-ray photoelectron spectroscopy confirms the charge transfer from\nCo<sub>5.47</sub>N to VN, which can further regulate the intrinsic\nelectronic structure and accelerate the ORR catalytic kinetics of\nVN/Co<sub>5.47</sub>N. Meanwhile, X-ray diffraction in combination\nwith transmission electron microscopy discloses abundant atomic defects\nin the VN/Co<sub>5.47</sub>N coupling interface, and such interfacial\ndisordered atoms and/or dangling bonds act as extra active sites for\neffective ORR catalysis. Benefiting from the interfacial electronic\nand atomic advantages, the as-prepared VN/Co<sub>5.47</sub>N realizes\nan ultralow half-wave potential of 0.81 V, high selectivity, and favorable\nstability. More importantly, the outstanding ORR performances of VN/Co<sub>5.47</sub>N endow the homemade Zn–air battery with VN/Co<sub>5.47</sub>N as an air cathode to afford outstanding performances\nin specific discharge capacity, power density, and discharge–charge\ncycle stability. This work paves the way for insight into the atomic\ninterface–performance relationship in ORR, and meanwhile, these\nfindings can be extended to design other active catalysts.