Strong Electronic Interaction Enhanced Electrocatalysis of Metal Sulfide Clusters Embedded Metal–Organic Framework Ultrathin Nanosheets toward Highly Efficient Overall Water Splitting

Abstract Unique metal sulfide (MS) clusters embedded ultrathin nanosheets of Fe/Ni metal–organic framework (MOF) are grown on nickel foam (NiFe‐MS/MOF@NF) as a highly efficient bifunctional electrocatalyst for overall water splitting. It exhibits remarkable catalytic activity and stability toward both the oxygen evolution reaction (OER, ƞ = 230 mV at 50 mA cm −2 ) and hydrogen evolution reaction (HER, ƞ = 156 mV at 50 mA cm −2 ) in alkaline media, and bi‐functionally catalyzes overall alkaline water splitting at a current density of 50 mA cm −2 by 1.74 V cell voltage without iR compensation. The enhancement mechanism is ascribed to the impregnated metal sulfide clusters in the nanosheets, which not only promote the formation of ultrathin nanosheet to greatly enlarge the reaction surface area while offering high electric conductivity, but more importantly, efficiently modulate the electronic structure of the catalytically active atom sites to an electron‐rich state via strong electronic interaction and strengthen the adsorption of oxygenate intermediate to facilitate fast electrochemical reactions. This work reports a highly efficient HER/OER bifunctional electrocatalyst and may shed light on the rational design and synthesis of uniquely structured MOF‐derived catalysts.