Bi-metallic MOF-derived in-plane intergrowth CoS2/MoS2 ultrathin nanosheets exhibit ultralow overpotential and long-term stability for alkaline HER electrocatalysis.

Layered transition-metal dichalcogenides (TMDs) have provided new opportunities for developing inexpensive and earthabundant catalysts for electrochemical hydrogen evolution reaction (HER). As the typical family members, semiconducting MoS 2 has been widely researched for HER electrocatalysis, while it has been rarely investigated for the emerging metallic VS 2 , despite high interest and great potential in this area. Herein, by using ultrasmall monolayer MoS 2 nanodots as size-controlled precursor, a lamellar heterostructure of MoS 2 nanodots and metallic VS 2 nanosheets (MoS 2 NDs/VS 2 ) is in situ hydrothermally integrated. Via tuning the hybridizing level of MoS 2 nanodots, the morphological and structural evolution of the product is explored, and the electrocatalytic HER performances are researched. The optimized hybrid is featured with thinner lamellar heterostructure, upgraded electrical conductivity, increased catalytically active sites and improved intrinsic activity, thus exhibiting significantly enhanced performance for HER electrocatalysis in acidic media. The possible synergistic interaction between the two counterparts is elucidated preliminarily. This work may pave the way for further investigations on TMDs-based heterostructure containing metallic VS 2 nanosheets, which shows great potential in broadening the horizon of electrocatalysis and materials chemistry.

A schematic representation of the ORR on Ni3S2/MoS2 nanosheets and HRTEM image of their heterointerfaces.