Fe and N co-doped carbon nanotube decorated with FexC derived by multiligand coordination self-assembly bimetallic complex for highly efficient oxygen reduction reaction†

Iron carbide assisted Fe–N–C electrocatalysts have attracted significant attention as promising candidates to enhance intrinsic activity in the oxygen reduction reaction (ORR), offering a viable alternative to Pt-based catalysts. However, their widespread development is impeded by challenges such as uncontrolled aggregation, the formation of large nanoparticles, and inefficient synthesis processes. Herein, we report a multiligand coordination self-assembly strategy to synthesize a novel metal–organic framework (MOF) precursor (FeZn-PBMI) with dual ligands and dual metals, followed by a thermal polymerization self-assembly process that successfully prepared FeN_x sites and Fe_xC atomic clusters decorating N-doped carbon nanotubes (Fe_xC@FeNCNTs) in gram-scale quantities. The ordered distribution of Zn and Fe within the FeZn-PBMI effectively prevents Fe aggregation during high-temperature pyrolysis, resulting in uniformly dispersed approximately 10 nm Fe_xC nanoparticles. As expected, the Fe_xC@FeNCNTs exhibit superior ORR performance with a half-wave potential of 0.87 V, surpassing commercial Pt/C (0.85 V), and demonstrate excellent long-term stability in Zn–air batteries with 1000 cycles. This synthetic approach may facilitate the development of highly active catalysts, advancing the practical application of Fe–N–C catalysts in various energy-related technologies.