Sandwich structured Ni3S2-MoS2-Ni3S2@Ni foam electrode as a stable bifunctional electrocatalyst for highly sustained overall seawater splitting

The exploitation of cost-effective bifunctional seawater electrocatalyst is an attractive technology to generate hydrogen fuel. Sustainable seawater splitting requires catalysts with robust hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity as well as superior chloride corrosion resistance in the salty electrolyte. Here we designed a sandwich-like Ni 3 S 2 -MoS 2 -Ni 3 S 2 @Ni foam (NMN-NF) catalyst on the surface of Ni foam by stacking Ni 3 S 2 coatings as top and bottom protective layers (chloride anti-corrosion), and MoS 2 as an interlayer to trigger both HER and OER in salty water. The unique sandwich structure endowed NMN-NF catalysts with excellent bifunctional catalytic activity and long-term durability in alkaline seawater electrolytes. Taking advantage of the synergistic effect between MoS 2 and Ni 3 S 2 , NMN-NF delivered a current density of 100 mA/cm 2 at a low voltage of 1.82 V under operating over 100 h in alkaline seawater, allowing them a promising catalyst towards practical application for efficient seawater splitting.