Introducing Mo ₂ C To Construct Multi-interfaces and Heterojunctions of NiFe Layered Double Hydroxide Realizes Electrocatalytic Overall Water Splitting in an Alkaline Medium

Developing cost-effective, high-performance, and stable electrocatalysts for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) remains a key challenge for the utilization of hydrogen energy. Herein, the heterostructure catalyst composed of NiFe-LDH coupled with Mo₂C materials and carbon nanospheres (NiFe/MC/C) is synthesized via a two-step integrated strategy. Benefiting from the tunable electronic structure of NiFe-LDH and the suitable hydrogen binding energy of MC materials, the synergistic effect between multi-interfaces and heterojunctions significantly enhances the water splitting performance of NiFe-LDH. The optimized catalyst affords low overpotentials of 232 mV for the OER and 151 mV for the HER at a current density of 10 mA cm^-2 in 1 M KOH. The cell voltage required for the 1.0NiFe/MC/C electrolytic cell is only 1.68 V at a current density of 50 mA cm^-2. The enhanced water splitting performance stems from the interfacial active sites, abundant channels, and significantly improved electrical conductivity. DFT calculations show that the rate-determining step energy barrier of NiFe-LDH/Mo₂C (1.66 eV) is significantly lower than that of NiFe-LDH (1.90 eV), thereby enhancing its OER performance. This research presents a facile and effective strategy for constructing multicomponent and high-performance electrocatalysts for overall water splitting.