CoFe-Layered Double Hydroxide Nanoarrays Interwoven with MoS2 Nanosheets as Electrocatalysts for Overall Water Splitting

Electrolysis for hydrogen production, a green and environmentally friendly method, still faces significant challenges. To achieve large-scale commercialization, a catalyst with long-term stability, large current density, high activity, and low cost is needed. In this study, a simple hydrothermal method is employed to prepare a nonprecious metal-based catalyst of molybdenum disulfide (MoS 2 ) and CoFe-layered double hydroxide (CoFe-LDH) grown on the surface of nickel foam (NF). The rich porosity of NF and the lamellar structure of CoFe-LDH provide abundant active sites and promote bubble escape. The MoS 2 on the CoFe-LDH surface not only further enhances the conductivity of CoFe-LDH but also provides additional electrochemical active surface area (ECSA) with its fluffy structure while modulating the electronic structure of the reactive active sites. These advantages make the sample MoS 2 /CoFe-LDH/NF exhibit substantially low overpotentials of 224/255/278 mV for oxygen evolution reaction (OER) and 211/297/331 mV for hydrogen evolution reaction (HER) at current densities of 10/50/100 mA cm –2, respectively, low Tafel slopes of 57.91 mV dec –1 for OER, and 113.17 mV dec –1 for HER. Moreover, the electrocatalyst presents good stability with no significant degradation after 250 h for OER and 200 h for HER at a large current density of 150 mA cm –2 . In full water electrolysis, it only requires 1.70 V to achieve a current density of 10 mA cm –2 . This study opened up a method for the design and synthesis of highly efficient bifunctional electrocatalysts for oxygen and hydrogen production.