Polyoxometalate superlattices derived bimetallic sulfides to accelerate acidic and alkaline hydrogen evolution...

Over the years, polyoxometalates (POMs) have been advocated as one of the most promising classes of molecular preassembly platform for the fabrication of highly efficient metal sulfide electrocatalysts. However, designing POMs-derived metal sulfides with high intrinsic activity, good site accessibility and structural stability for both acidic and alkaline hydrogen evolution reaction (HER) remains a great challenge because of the self-aggregation and random distribution of traditional POM precursors. Herein, we have designed a bimetallic sulfide eventually encapsulated by C₃N₄ walls (CoMoS@CN) for efficient HER based on a simple hydrothermal and subsequent high-temperature vulcanization using the well-designed POM superlattice assembly as precursor. The organized superlattice structure with long-range ordered arrangements of POM units provide chance to prevent the agglomeration of metal sites. The in-situ formed exterior C₃N₄ protective wall can accelerate the electron transfer and protect catalyst from chemical corrosion in different electrolyte. The merits combining with a large specific surface area enable CoMoS@CN with remarked HER performance of low overpotentials of 164 and 95 mV at 10 mA cm^-2 in acidic and alkaline conditions. Such results are better than that of p-CoMoS@CN synthesized by pyrolysis of the corresponding physical mixtures and other comparative single metal sulfides.