Multiscale structural engineering of atomically dispersed FeN4 electrocatalyst for proton exchange membrane fuel cells

Atomically dispersed iron-nitrogen-carbon (Fe-N-C) catalysts have emerged as the most promising alternative to the expensive Pt-based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), however suffer from low site density of active Fe-N-4 moiety and limited mass transport during the catalytic reaction. To address these challenges, we report a three-dimensional (3D) metal-organic frameworks (MOF)-derived Fe-N-C single-atom catalyst. In this well-designed Fe-N-C catalyst, the micro-scale interconnected skeleton, the nano-scale ordered pores and the atomic-scale abundant carbon edge defects inside the skeleton significantly enhance the site density of active Fe-N-4 moiety, thus improving the Fe utilization in the final catalyst. Moreover, the combination of the above mentioned micro- and nano-scale structures greatly facilitates the mass transport in the 3D Fe-N-C catalyst. Therefore, the multiscale engineered Fe-N-C single-atom catalyst achieves excellent ORR performance under acidic condition and affords a significantly enhanced current density and power density in PEMFC. Our findings may open new opportunities for the rational design of Fe-N-C catalysts through multiscale structural engineering. (C) 2020 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 3D metal-organic frameworks-derived Fe-N-C single-atom catalyst reported in this study enhances the site density of active Fe-N-4 moiety and facilitates mass transport, leading to excellent performance in the oxygen reduction reaction in proton exchange membrane fuel cells.