Binary ligand strategy toward interweaved encapsulation-nanotubes structured electrocatalyst for proton exchange membrane fuel cell

Hierarchically porous architecture of iron-nitrogen-carbon (Fe-N-C) for oxygen reduction reaction (ORR) is highly desired towards efficient mass transfer in the fuel cell device manner. Herein, we reported a binary ligand strategy to prepare zeolitic imidazolate frameworks (ZIFs)-derived precursors, wherein the addition of secondary ligand endows precursors with the capabilities to transform into porously interweaved encapsulation-nanotubes structured composites after calcination. The optimal catalyst, i.e., termed as Fe-6-M/C-3, exhibits excellent durability with 88.8% current retention after 50,000 seconds in 0.1 M HClO4 solution by virtue of nanoparticles-encapsulation features, which is more positive than the benchmark commercial 20 wt% Pt/C catalyst. Moreover, a promising maximum power density of Fe-6-M/C-3 as cathode catalyst was also demonstrated in proton exchange membrane fuel cells (PEMFCs) measurements. Therefore, this binary ligand approach to the fabrication of hierarchically porous structures would also have significant implications for various other electrochemical reactions. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

The hierarchically porous Fe-N-C structure prepared using a binary ligand strategy shows excellent durability and high current retention, outperforming benchmark catalysts. The catalyst also demonstrates a promising maximum power density in proton exchange membrane fuel cells, indicating significant implications for various electrochemical reactions.