Interface Engineering of Crystalline-Amorphous Heterostructures with Strong Electronic Interactions for Efficient Alkaline Overall Water Splitting

The rational design of high-active, stable, and inexpensive bifunctional transition-metal-based electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is a crucial challenge to achieve efficient hydrogen production via overall water splitting. Herein, we fabricate core-shell heterostructure nanoparticles by electrodepositing ultrathin amorphous CoFe hydroxides on crystalline Mo-doped Ni3S2 with nickel foam as substrate (Mo-Ni3S2/CoFeOH/NF). The results of physical characterizations and electrochemical measurements show the unique Mo-Ni3S2/CoFeOH/NF heterostructure material contributes to optimized electron structure, low charge transfer resistance, and high electrochemical active surface area. Finally, the Mo-Ni3S2/CoFeOH/NF displays excellent performance to achieve 10 mA/cm2 with a low overpotential of 109 mV for HER and 246 mV for OER, and only needs 1.51 V for overall water splitting. This work provides a new perspective for interface engineering of superior electrocatalysts toward hydrogen production.