From Metal-Organic Frameworks to Single-Atom Fe Implanted N-doped Porous Carbons: Efficient Oxygen Reduction in Both Alkaline and Acidic Media.

It remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal-organic frameworks (MOFs) have been synthesized based on a novel mixed-ligand strategy to afford high-content (1.76 wt %) single-atom (SA) iron-implanted N-doped porous carbon (Fe -N-C) via pyrolysis. Thanks to the single-atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized Fe -N-C exhibits excellent oxygen reduction activity and stability, surpassing almost all non-noble-metal catalysts and state-of-the-art Pt/C, in both alkaline and more challenging acidic media. More far-reaching, this MOF-based mixed-ligand strategy opens a novel avenue to the precise fabrication of efficient single-atom catalysts.