Contracted Fe-N-C Sites in Single-Atom Catalysts Boosting Catalytic Performance for Oxygen Reduction Reaction.

Promoting the catalyst performance for oxygen reduction reaction (ORR) in energy conversion devices through controlled manipulation of the structure of catalytic active sites has been a major challenge. In this work, we prepared Fe-N-C single-atom catalysts (SACs) with Fe-N active sites and found that the catalytic activity of the catalyst with shrinkable Fe-N-C sites for ORR was significantly improved compared with the catalyst bearing normal Fe-N-C sites. The catalyst C@PVI-(TPC)Fe-800, prepared by pyrolyzing an axial-imidazole-coordinated iron corrole precursor, exhibited positive shifted half-wave potential ( = 0.