Structural Distortion for Polyoxometalate‐Derived Metal Sulfide Induced by In Situ Intercalation With Organic Ligands Achieving Efficient Electrocatalytic Hydrogen Evolution Performance in Alkaline/Seawater Medium

ABSTRACT

The electrocatalytic water splitting technique was widely taken for hydrogen evolution, due to its cost‐effectiveness and environmental friendliness. The design of electrode material as electrocatalysts play a key role in achieving high efficiency. In this work, bimetallic Ni–Mo sulfide‐based heterostructure, originating from a polyoxometalates‐based metal–organic complex, grew on carbon fiber with a nano‐size. Bimetallic sulfide‐based nanosheets aggregated as nanowires around the carbon fiber and exposed abundant active sites. The organic ligand from the complex was intercalated between the interlayers, resulting in structural distortion and an enlarged lattice distance for the heterostructure. The intercalation also induced the phase transition for MoS ₂ , enabling the coexistence of 1T and 2H phases. The optimized structure and composition generated rich active sites and promoted electron transfer during the electrocatalytic process. NiS ₂ –MoS ₂ /CC‐48 exhibited remarkable electrocatalytic activity and achieved the overpotential of 54/87 mV at the current density of 10 mA cm ⁻² in 1 M KOH/simulated seawater, respectively. The highly exposed active surface brought from the nanofibers contributed to the desorption of Ca ²⁺ and benefited the stability in the seawater environment. The electrode material also demonstrated excellent electrocatalytic stability under industrial current density conditions.