Gadolinium‐Induced Valence Structure Engineering for Enhanced Oxygen Electrocatalysis

Rare earth doped materials with unique electronic ground state configurations are considered emerging alternatives to conventional Pt/C for the oxygen reduction reaction (ORR). Herein, gadolinium (Gd)‐induced valence structure engineering is, for the first, time investigated for enhanced oxygen electrocatalysis. The Gd₂O₃–Co heterostructure loaded on N‐doped graphene (Gd₂O₃–Co/NG) is constructed as the target catalyst via a facile sol–gel assisted strategy. This synthetic strategy allows Gd₂O₃–Co nanoparticles to distribute uniformly on an N‐graphene surface and form intimate Gd₂O₃/Co interface sites. Upon the introduction of Gd₂O₃, the ORR activity of Gd₂O₃–Co/NG is significantly increased compared with Co/NG, where the half‐wave potential (E_1/2) of Gd₂O₃–Co/NG is 100 mV more positive than that of Co/NG and even close to commercial Pt/C. The density functional theory calculation and spectroscopic analysis demonstrate that, owing to intrinsic charge redistribution at the engineered interface of Gd₂O₃/Co, the coupled Gd₂O₃–Co can break the OOH*–OH* scaling relation and result in a good balance of OOH* and OH* binding on Gd₂O₃–Co surface. For practical application, a rechargeable Zn–air battery employing Gd₂O₃–Co/NG as an air–cathode achieves a large power density and excellent charge–discharge cycle stability.