Utilizing an electron redistribution strategy to inhibit the leaching of sulfur from CeO₂/NiCo₂S₄ heterostructure for high-efficiency oxygen evolution

Developing highly active and robust transition metal chalcogenides (TMCs) electrocatalysts toward oxygen evolution reaction (OER) remains a challenge. Herein, we report an electron redistribution mechanism that involves the metal-sulfur (M-S) bond stabilization triggered by electron transfer from Ce to Ni and Co in CeO2/ NiCo2S4 heterostructure, thereby effectively inhibiting the leaching of sulfur from CeO2/NiCo2S4 during the OER process. Moreover, the well-modulated heterogeneous interface enables optimal adsorption affinity for oxygen intermediates and reduces the energy barrier of OER. As a result, CeO2/NiCo2S4 exhibits superior OER activity with ultralow overpotentials of 146 and 271 mV at 10 and 100 mA cm-2, respectively. More importantly, CeO2/ NiCo2S4 possesses excellent durability for over 200 h at 500 mA cm-2, surpassing individual NiCo2S4 and most of the reported TMCs-based electrocatalysts. This work provides new insights for achieving good compatibility of TMCs-based OER electrocatalysts in terms of high activity and stability.