Core-Shell Fe3O4@NCS-Mn Derived from Chitosan-Schiff Based Mn Complex with Enhanced Catalytic Activity for Oxygen Reduction Reaction

A core-shell type of Fe3O4/NCS-Mn composite was prepared by pyrolyzing a precursor fabricated by coating a chitosan-Schiff base Mn complex on Fe3O4 cores. For comparison purposes, the Fe3O4@NCS sample in the absence of Mn and the Fe3O4@NC sample derived from just chitosan coating Fe3O4 were also prepared. Among the three catalysts, Fe3O4@NCS-Mn demonstrates the best electrocatalytic activity compared to commercial Pt/C (20%) for oxygen reduction reaction (ORR). The average of the transferred electron number (n) approached 3.6 in the range of -0.3 to -0.8 V (vs. Ag/AgCl). Moreover, the catalyst exhibited high stability and durability against methanol and may potentially be a promising ORR catalyst for fuel cells.