Unraveling the synergistic effect of defects and interfacial electronic structure modulation of pealike CoFe@Fe3N to achieve superior oxygen reduction performance

Engineering of defect and interface are two effective strategies to regulate the electronic structure and electrocatalytic activities. However, integrated the synergistic effect of carbon/oxygen defects and interfacial effects into spinel derivatives to dramatically improve the electrocatalytic property has not been studied up till now. Herein, a CoFe@Fe3N hybrid embedded into N-doped carbon nanotube has been prepared by heat-treatment of CoFe2O4 using a simple chemical vapor deposition method. Impressively, the as-prepared CoFe@Fe3N-CNT catalyst manifests a prominent stability and catalytic performance towards the oxygen reduction reaction (ORR), as demonstrated by an ultrahigh half-wave potential (E1/2) of 0.936 V, which is the best ORR spinel-based catalysts. Furthermore, it was assembled into a rechargeable ZAB, which showed a high-power density of 173.6 mW cm-2 and an open circuit voltage of 1.534 V. The enhanced electrochemical performances are primarily due to the synergistic effect of carbon-oxygen double defects and interfacial electronic structure modulation.