Abstract:

Ammonium ferric citrate was used as the Fe source to be incorporated into the leaf like ZIF-L precursor,and the two-dimensional flake Fe-NC catalyst with good morphology was successfully prepared by stepwise pyrolysis.By optimizing Fe content in the precursors,the Fe-NC-1% catalyst was found to exhibit outstanding oxygen reduction reaction（ORR） per-formance in alkaline electrolytes,with the half-wave potential（E_1/2） of 0.897 V,kinetic current density（J_{0.85 V}） of 26.70 mA/cm²and Δ E_1/2 reducing 5 mV after 5 000 cycles,which were all better than those of commercial Pt/C catalyst.The results combining with Raman spectrum,XPS and BET（specific surface area） method showed that the large specific surface area,high graphitization degree,and abundant N-containing active species of Fe-NC-1% led to the high mass transfer efficiency and utilization rate of catalytic active sites,which was an important factor to promote the ORR reaction kinetics.

Key words: oxygen reduction reaction, ZIF-L, N-doped carbon, Fe-based catalysts