Boosting the Performance of Iron-Phthalocyanine as Cathode Electrocatalyst for Alkaline Polymer Fuel Cells Through Edge-Closed Conjugation

Recent progress in anion-exchange membranes has evoked increasing interests in alkaline polymer fuel cells (APFCs). A large body of recent research has demonstrated attractive activity of Fe-N macrocycle complexes as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media. To be a substitute for Pt in APFCs, however, most of the macrocycle molecules remain largely unsatisfactory in both of the catalytic activity and durability. Herein, we show that a one-pot microwave conjugation results in a polymerized iron-phthalocyanine (pFePc) which exhibits extremely high ORR performance, showing activity much better than that of the FePc monomer and 20 wt % Pt/C, and similar to that of the 60 wt % Pt/C under the same catalyst loading. Furthermore, we proposed an edge-closing strategy to significantly enhance the stability of the pFePc catalyst in alkaline media by eliminating the edge anhydride groups. Using the edge-closed pFePc as the cathode catalyst in APFC, a power density as high as 452 mW·cm^-2 is achieved, which is among the best performance of non-noble metal catalyst-based APFCs so far reported.