Interface engineering of double-layered nanosheets via cosynergistic modification by LDH interlayer carbonate anion and molybdate for accelerated industrial water splitting at high current density

• Comodification of Molybdate and LDH interlayer carbonate anion. • The construct of atomic-level coupled heterostructure (NFCH-NMO). • The interface engineering with high energy phase boundary effect. • The NFCH-NMO exhibit distinguished performance for overall water splitting. Favorable regulation of electronic coordination environment, especially combined with the interface engineering with synergistic effects to design efficient, stable and low-cost transition-metal-based catalysts for industrial electrocatalytic overall water splitting (EOWS) is a key renewable energy technology, but still facing a daunting challenge. Here, molybdate modification cooperates with LDH interlayer carbonate anion to construct atomic-level coupled heterostructure (NFCH-NMO), and the resulting strong electron interaction at the two-phase interface to directly optimize the electronic structure and d-band center of NiFe-based catalyst. Owing to the high-energy phase boundary effect and the rapid mass transfer advantages of the 3D mesoporous super-hydrophilic surface, the as-prepared NFCH-NMO exhibits remarkable oxygen and hydrogen evolution reaction (OER/HER) catalytic activity, with low overpotentials of 219/203 and 289/297 mV at 50 and 500 mA·cm −2 , respectively. The alkaline water electrolyzer of NFCH-NMO || NFCH-NMO only requires a cell potential of 1.66 and 1.839 V to reach 50 and 500 mA·cm −2 . This work provides a well-defined catalyst for EOWS at high current density and shows the interfacial engineering of heterostructure with the high-energy interface effect via synergistic modification of LDH interlayer carbonate anion and molybdate is a suitable strategy to enhance the internal electrocatalytic performance of NiFe based catalysts.