Mesopore-tuned iron and nitrogen co-doped carbon for enhanced oxygen reduction electrocatalysis

Pore-tuning engineering has been proven as an effective strategy in catalyst design for energy storage and conversion. Herein, we propose a rhombic dodecahedral iron and nitrogen co-doped carbon-based material (Fe-N-C) with hierarchical micro-mesoporous structures using mesoporous silica as the pore template and iron launch vehicle. The as-prepared catalysts (m-Fe/NC) exhibit much boosted ORR activity with half-wave potential of 0.81 V and 0.88 V in acidic and alkaline media, respectively. Furthermore, a superior specific capacity of 815 mAh gZn−1 and stable cell voltage of 1.31 V is achieved at current density of 10 mA cm−2 when using m-Fe/NC as cathode for zinc-air batteries (ZAB). Advanced characterization techniques and theoretical calculations reveal that the introduction of mesopore structure not only improves the active site exposure, but also the proper curvature-induced strain effect from mesoporous concave surface enhances the intrinsic activity. This work provides significant insights for future development of innovative nanoporous electrocatalysts.