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-Nxspecies.Our catalyst shows superior ORR performance with positive half-wave potential(E1/2=0.85 V vs.RHE)in alkaline condition and moderate activity(E1/2=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.