Amino-metalloporphyrin polymers derived Fe single atom catalysts for highly efficient oxygen reduction reaction

Recently, nitrogen-doped porous carbon supported single atom catalysts (SACs) have become one of the most promising alternatives to precious metal catalysts in oxygen reduction reaction (ORR) due to their outstanding performance, especially those derived from porphyrin-based materials. However, most of them involve other metal residuals, which would cause the tedious pre- and/or post-treatment, even mislead the mechanistic investigations and active-site identification. Herein, we report a precursor-dilution strategy to synthesize Fe SACs through the Schiff-based reaction via co-polycondensation of amino-metalloporphyrin, followed by pyrolysis at high temperature. Systematic characterization results provide the compelling evidence of the dominant presence of atomically dispersed Fe-N(x)species. Our catalyst shows superior ORR performance with positive half-wave potential (E-1/2=0.85 V vs. RHE) in alkaline condition and moderate activity (E-1/2=0.68 V vs. RHE) under the acidic condition, excellent methanol tolerance and good long-term stability. All the results indicate Fe SACs would be a promising candidate for replacing the precious Pt in metal-air batteries and fuel cells.