Interfacial Electric Field Stabilized Ru Single-Atom Catalysts for Efficient Water Oxidation

Suppressing the overoxidation and dissolution of active-Ru single-atom catalysts (SACs) is highly desirable to realize an efficient and durable oxygen evolution reaction (OER), yet overcoming the trade-off relationship between activity and stability of SACs remains challenging. Here, we present a local electronic regulation strategy for the synthesis of a core−shell Ni3S2/NiO heterostructure (NiO@Ru−Ni3S2) to stabilize single-atom Ru sites. The obtained NiO@Ru−Ni3S2 catalyst exhibits superior OER activity and long-term durability, requiring an overpotential of only 110 mV to drive a current density of 10 mA cm−2, and a Tafel slope as low as 22.6 mV dec−1, surpassing the state-of-the-art OER catalysts that have been reported. Experimental analyses and theoretical calculations revealed that the built-in electric field induced by work functions triggers the directional electron transfer from Ni3S2 to NiO and the formation of electron-rich regions around Ru atoms, which effectively suppresses the overoxidation and dissolution of the single-atom Ru sites, thus realizing the dual optimization of activity and durability.