Facile preparation of trace-iron doped manganese oxide/N-doped ketjenblack carbon composite for efficient ORR electrocatalyst

Abstract Low-cost and highly efficient catalysts toward oxygen reduction reaction (ORR) are extremely required for the rapid development of Al-air batteries. Herein, novel trace-iron doped manganese oxide/N-doped ketjenblack carbon composites (Fe–MnO x /N–KB) were prepared by a facie and scalable route using cheap, more abundant, and commercially available raw materials ( i.e. manganese sulfate, ferrous nitrate, melamine and KB). The proposed route only consisted of one-pot hydrothermal treatment and subsequent a mild calcination process. The high spefic area and synergistic effect from Fe–N–C active sites and Mn 3+ greatly boosted the ORR activity. As a result, Fe–MnO x /N–KB showed superior ORR activity in terms of positive half-wave potential (0.78 V) and high limiting current density (5.8 mA/cm 2 ), comparable to those of commercial Pt/C (0.82 V, 5.3 mA/cm 2 ). Moreover, Fe–MnOx/N–KB exhibited excellent catalytic stability. When used as cathode catalyst in home-made Al-air battery, Fe–MnO x /N–KB showed higher discharge voltage (1.51 V) at constant current density of 50 mA/cm 2 than that of commercial Pt/C (1.46 V). Considering its low cost, high efficiency and scalable preparation, Fe–MnO x /N–KB has great potential to substitute commercial Pt/C for ORR.