The thermodynamically stable phase of molybdenum disulfide (MoS2) is evaluated as a promising and durable nonprecious-metal electrocatalyst toward the hydrogen evolution reaction (HER); however, its actual catalytic activity is restricted by an inert basal plane, low electronic conductivity, low density, and using efficiency of edged atoms. Moreover, 2D/2D van der Waals (vdws) heterostructures (HSs) with face-to-face contact can construct a highly coupled interface and are demonstrated to have immense potential for catalytic applications. In the present work, a 2D/2D hetero-layered architecture of an electrocatalyst, based on the alternate arrangement of ultrasmall monolayer MoS2 nanosheets (approximately 5–10 nm) and ultrathin graphene (G) sheets, is prepared by a facilely chemical process, which is named as MoS2/G HS. The unique structural characteristic of MoS2/G HS is in favor of accommodating more active sites as the centers of ad/desorption hydrogen and transferring and separating the charges at a coupled interface to improve the electronic conductivity and durability. The density functional theory calculation results further confirm that the alternately arranged G layers and MoS2 monolayers, as well as the expanded interplanar distance of 1.104 nm for MoS2/G HS, can exhibit a superior HER performance in both 0.5 M H2SO4 and 1.0 M KOH.

A PVP incorporated MoS2 host with enhanced durability due to the role of PVP in tightly bridging MoS2 monolayers.

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Owing to the low-cost, dendrite-free formation, and high volumetric capacity, rechargeable Li + /Mg 2+ hybrid-ion batteries (LMIBs) have attracted great attention and are regarded as promising energy storage devices. However, due to the strong Coulombic interaction of Mg 2+ with host materials, the traditional "Daniell Type" LMIBs with only Li + intercalation usually cannot ensure a satisfactory energy density. Herein, graphene monolayers are arranged intercalating into MoS 2 interlamination to construct van der Waals heterostructures (MoS 2 /G VH). This operation transforms the construction of ion channels from pristine interlamination of two MoS 2 monolayers to the interlamination of MoS 2 monolayer with graphene monolayer, thereby greatly reducing ion diffusion energy barriers. Compared with pristine MoS 2 , the MoS 2 /G VH can obviously reduce the migration energy barriers of Li + (from 0.67 to 0.09 eV) and Mg 2+ (from 1.01 to 0.21 eV). Moreover, it is also demonstrated that MoS 2 /G VHs realize Li + /Mg 2+ co-intercalation even at a rate current of 1000 mA g −1 . As expected, the MoS 2 /G VH exhibits superior electrochemical performance with a reversible capacity of 145.8 mAh g −1 at 1000 mA g −1 after 2200 cycles, suggesting the feasibility of potential applications for high-performance energy storage devices.

Compared with the strategy of expanding MoS2 interlayer spacing, constructing van der Waals heterostructures of MoS2 and graphene (MoS2/G) has proven to be a more effective method to facilitate the...