Engineering heterostructure of bimetallic nickel-silver sulfide as an efficient electrocatalyst for overall water splitting in alkaline media

Bimetallic composites have been widely utilized as high-active catalysts in electrochemical reactions due to the synergistic effect at the interfaces of the hybrid-boundaries. However, there are few reports on the application of bimetallic sulfides. Herein, a facile one-step strategy was designed and implemented to prepare the bimetallic nickel-silver sulfides with heterostructure as high-efficiency water electrolysis catalysts. The optimal Ag2S and NiSx combo-catalyst outputs activities towards both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). At 10 ​mA ​cm−2, the overpotentials for OER and HER are 260 ​mV and 230 ​mV, respectively, which are close or even superior to those observed on Pt- and IrO2-/RuO2-based precious catalysts. On one hand, Ag2S/Ag doped in NiSx fascinates the electron transfer between the abundant interfaces, and on the other hand, hetero-doping also induces Ni species oxidation to NiOOH active intermediate for OER, thus accelerating the reaction rate. Therefore, the well-prepared bimetallic Ag2S-NiSx materials demonstrated higher synergistic catalytic activities for both OER and HER.