Riveted Fe–N5 moieties confined in curved graphitic carbon enable a triple-protection mechanism for robust acidic oxygen reduction electrocatalysis

Rational design integrating curvature and axial coordination enhances both activity and stability. • OTD induced strategy rivets the curved Fe–N 5 sites into porous graphitic carbon. • In MEA tests, the catalyst achieves 1.37 W cm −2 peak power,loses only 10.2% after 10k cycles, and retains 74.3% current at 0.65 over h. • Curved Fe–N 5 motifs tune electronic states and offer triple protection against Fe dissolution, carbon corrosion, and H⁺ attack. Fe–N–C exhibits exceptional catalytic activity and stands as a prominent representative of single-atom catalysts (SACs). However, the activity and, especially, the stability of its active sites pose a formidable challenge for practical applications. Therefore, we first performed DFT predictions on active site structural models featuring curvature and axial coordination, revealing that the curved Fe–N 5 configuration simultaneously boosts both the activity and stability. Then we adopt an O-Tolidine molecular-induced strategy to construct the curved graphitic carbon layers, which anchor Fe single atoms in a bent and axial N-coordinated configuration. The molecular-assisted effect facilitates micropore formation, accelerates the graphitization process, and simultaneously provides additional nitrogen coordination sites, ultimately achieving the curved Fe–N 5 configuration. The curved Fe–N 5 motifs establish a triple protection mechanism: resistance to Fe dissolution, suppression of carbon corrosion and shielding against H⁺ attack, thus alleviating the long-standing activity–stability trade-off in SACs. Benefiting from these structural merits, the as-obtained catalyst delivers outstanding durability in H 2 -O 2 fuel cell, achieving a high peak power density of 1.37 W cm −2 with only 10.2% performance degradation after 10,000 square-wave cycles—far lower than the 29.8% loss of conventional Fe–N–C. Under H 2 -Air conditions at 0.65 V, it retains 74.3% of its initial current density over 200 h. Download: Download high-res image (242KB) Download: Download full-size image