Synergistic design of Mo-intercalated NiSe2: a binary transition metal chalcogenide for highly efficient bifunctional seawater electrolysis

Developing highly efficient and low-cost catalysts for water-splitting is crucial for long-term energy conversion. Herein, we synthesized the Mo-intercalated NiSe 2 –ternary NiMoSe 2 through a simple solvo/hydrothermal route. The synthesized materials were characterized structurally and morphologically using XRD, XPS, FESEM, TEM, and SAED. The designed electrocatalyst has outstanding catalytic capabilities for hydrogen and oxygen evolution reactions in alkaline conditions, with an ultra-small Tafel slope value of 53 mV dec −1 for hydrogen evolution and 63 mV dec −1 for oxygen evolution. The excellent bifunctional catalytic performance of ternary NiMoSe 2 should be due to the electronic modulation and synergistic impact between Ni and Mo, the intrinsic metallic conductivity, and the increased active site exposure. It is shown that the ternary NiMoSe 2 is an excellent bifunctional electrocatalyst for seawater splitting, producing a current density of 10 mA cm −2 at overpotentials of 105 and 285 mV for OER and HER in alkaline seawater, respectively, following the Heyrovsky mechanism with outstanding long-term stability. This finding offers a new approach towards the construction of efficient catalysts for hydrogen generation from seawater. Graphical abstract