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 Gd 2 O 3 –Co heterostructure loaded on N‐doped graphene (Gd 2 O 3 –Co/NG) is constructed as the target catalyst via a facile sol–gel assisted strategy. This synthetic strategy allows Gd 2 O 3 –Co nanoparticles to distribute uniformly on an N‐graphene surface and form intimate Gd 2 O 3 /Co interface sites. Upon the introduction of Gd 2 O 3 , the ORR activity of Gd 2 O 3 –Co/NG is significantly increased compared with Co/NG, where the half‐wave potential (E 1/2 ) of Gd 2 O 3 –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 Gd 2 O 3 /Co, the coupled Gd 2 O 3 –Co can break the OOH*–OH* scaling relation and result in a good balance of OOH* and OH* binding on Gd 2 O 3 –Co surface. For practical application, a rechargeable Zn–air battery employing Gd 2 O 3 –Co/NG as an air–cathode achieves a large power density and excellent charge–discharge cycle stability.