摘要
Fe-NX/C electrocatalysts have aroused extensive interest in accelerating sluggish oxygen reduction reaction (ORR) kinetics as potential alternatives to platinum catalysts in rechargeable Zn-air batteries (ZABs).However,the low density and poor accessibility of Fe-NXsites have severely restricted the electrocatalytic performance of Fe-NX/C.Herein,Fe,N co-doped ordered mesoporous carbon fiber bundles are prepared through a ligand-assisted strategy with nitrogen-rich 1,10-phenanthroline as space isolation agent.1,10-Phenanthroline reveals a six-membered heterocyclic structure containing abundant nitrogen species to tightly coordinate with Fe ions,which is conducive to achieving high-density Fe-NXsites.Meanwhile,the adoption of SBA-15 as hard-templates enables the catalysts with highly ordered channels and large specific surface areas,improving the accessibility of Fe-NXsites.The optimal catalyst (PDA-Fe-900) demonstrates a positive half-wave potential of 0.84 V (vs.RHE) in alkaline solution,outperforming the commercial Pt/C (0.83 V).In addition,PDA-Fe-900 delivers comparable ORR performance to commercial Pt/C in acidic electrolyte.Impressively,when PDA-Fe-900 is employed as an air cathode,it achieves large power densities of 163.0 m W/cm^(2) in liquid-state ZAB and 116.6 m W/cm^(2) in the flexible solid-state ZAB.This work provides an efficient ligand-assisted pathway for fabricating catalysts with dense and accessible FeNXsites as high-performance ORR electrocatalysts for ZABs.
基金
supported by the National Natural Science Foundation of China(No.U1804255)
the Key Research&Development and Promotion Projects in Henan Province(Nos.222102520038 and 212102210651)。
