Synthesis of bimetallic sulfides using a crystalline polyoxometalate-based coordination polymer achieved efficient hydrogen evolution reaction

The development of non-noble and efficient electrocatalysts is crucial for hydrogen production through water splitting. Herein, we design and synthesis of a novel crystalline polyoxometalate-based metal–organic compound [{Cu(bipy)}6(MoVI6O22)](PMoVMoVI11O40). The structure of the compound was confirmed by single-crystal X-ray diffraction, which exhibits an unusual one-dimensional chain consisting both heteropolyanions and isopolyanions. The Cu and Mo are uniform and possess a fixed proportion at a molecular level in the chain. Thus, the compound was subsequently utilized as a precursor to react with thiourea (TU) and bimetallic sulfides were in-situ formed, which directly couple onto carbon cloth (CC) to create an electrode MoS2-Cu2S-CC. The electrode was characterized by various measurements, and the results show that the bimetallic sulfides are uniformly distributed throughout the electrode and exhibit a highly dispersed naono-sheet morphology. Owing to the synergistic effect between the uniform bimetallic sulfides, the MoS2-Cu2S-CC composite demonstrates a low overpotential of 159 mV and a smaller slope of 109 mV dec-1 at a current density of 10 mA cm−2 under an alkaline condition. The electrocatalytic performance of the MoS2-Cu2S-CC exceeds that many POM and/or MoS2-based catalysts. This study provides a straightforward strategy for preparing highly dispersed bimetallic sulfides with exceptional electrocatalytic hydrogen evolution reaction (HER) performance.