Mn-doped perovskite-type oxide LaFeO3 as highly active and durable bifunctional electrocatalysts for oxygen electrode reactions

Abstract

Perovskite oxides based on the alkaline earth metal lanthanum for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolytes are promising catalysts, but their catalytic activity and stability remain unsatisfactory. Here, we synthesized a series of LaFe1−xMnxO3 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) perovskite oxides by doping Mn into LaFeO3 (LF). The results show that the doping amount of Mn has a significant effect on the catalytic performance. When x = 0.5, the catalyst LaFe0.5Mn0.5O3 (LFM) exhibits the best performance. The limiting current density in 0.1 mol·L−1 KOH solution is 7 mA·cm−2, much larger than that of the commercial Pt/C catalyst (5.5 mA·cm−2). Meanwhile, the performance of the doped catalyst is also superior to that of commercial Pt/C in terms of the long-term durability. The excellent catalytic performance of LFM may be ascribed to its abundant O2−/O− species and low charge transfer resistance after doping the Mn element.