Enhanced ORR Performance of Gd Doped MnO2: The Critical Role of f-electron Modulation

Abstract

Manganese oxides have gained extensive attention in recent years for their application in oxygen reduction reaction (ORR). Among them,cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2), with its unique tunnel structure, is frequently employed as a host material for doping modifications. Lanthanide elements possess distinct f-electron configurations, yet their role in such catalytic systems remains underexplored. In this study, rare earth elements (La 4f0, Gd 4f7, Lu 4f14) were introduced into the molecular tunnels of OMS-2 to enhance the catalytic performance of manganese-based catalysts. Among the synthesized catalysts, Gd-doped OMS-2 (OMS-Gd) exhibited the highest ORR activity, which is attributed to its half-filled f-orbital electronic configuration. The f-electrons do not directly participate in surface chemical reactions, they regulate the performance of the Mn directly involved in the reaction via the Gd-O-Mn interaction. As a proof of concept, a zinc-air battery assembled with OMS-Gd as the cathode catalyst exhibits superior power density and cycling stability compared to commercial Pt/C. This work offers a rational strategy for designing high-performance rare-earth-doped electrocatalysts.