Dynamic in situ reconstruction of NiSe2 promoted by interfacial Ce2(CO3)2O for enhanced water oxidation

Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity. Herein, we present a synthesis of NiSe 2 -Ce 2 (CO 3 ) 2 O heterostructure and demonstrate the efficacy of interfacial Ce 2 (CO 3 ) 2 O in promoting the formation of catalytically active centers to improve oxygen evolution activity. In-situ Raman spectroscopy shows that incorporation of Ce 2 (CO 3 ) 2 O into NiSe 2 causes a cathodic shift of the Ni 2+ →Ni 3+ transition potential. Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heterogeneous interface accelerates charge transfer process. Furthermore, density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe 2 , which is coupled with Ce 2 (CO 3 ) 2 O, can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction (OER) kinetics. Consequently, the resultant NiSe 2 -Ce 2 (CO 3 ) 2 O electrode exhibits remarkable electrocatalytic performance with low overpotentials (268/304 mV @ 50/100 mA cm −2 ) and excellent stability (50 mA cm −2 for 120 h) in the alkaline electrolyte. This work emphasizes the significance of modulating the dynamic changes in developing efficient electrocatalyst.