Construction of an Advanced NiFe-LDH/MoS-NiS/NF Heterostructure Catalyst toward Efficient Electrocatalytic Overall Water Splitting.

Developing high-efficiency, low-cost, and earth-abundant electrocatalysts toward the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) is highly desirable for boosting the energy efficiency of water splitting. Herein, we adopted an interfacial engineering strategy to enhance the overall water splitting (OWS) activity via constructing a bifunctional OER/HER electrocatalyst combining MoS-NiS with NiFe layered double hydroxide (NiFe-LDH) on a nickel foam substrate. The NiFe-LDH/MoS-NiS/NF electrocatalyst delivers superior OER/HER activity and stability, such as low overpotentials (220 and 79 mV for OER and HER at current densities of 50 and 10 mA cm, respectively) and a low Tafel slope. This excellent electrocatalytic performance mainly benefits from the electronic structure modulation and synergistic effects between NiFe-LDH and MoS-NiS, which provides a high electrochemical activity area, more active sites, and strong electron interaction. Furthermore, the assembly of NiFe-LDH/MoS-NiS/NF into a two-electrode system only requires an ultra-low cell voltage of 1.50 V at a current density of 10 mA cm and exhibits outstanding stability with a decay of current density of only 2.11% @50 mA cm after 50 h, which is far superior to numerous other reported transition metal NiFe-LDH and MoS-NiS-based as well as RuO||Pt-C electrocatalysts. This research highlights the rational design of heterostructures to efficiently advance electrocatalysis for water splitting applications.