Design of MoS₂/Graphene van der Waals Heterostructure as Highly Efficient and Stable Electrocatalyst for Hydrogen Evolution in Acidic and Alkaline Media

Abstract

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.

Electrocatalytic Hydrogen Evolution Reaction Related to Nanochannel Materials

“…[66] For example, Zhang and co-workers have fabricated a heterostructure with alternatively arranged ultrasmall monolayer MoS 2 nanosheets and ultrathin graphene (Figure 5b). [25] The density functional theory calculation illustrates an expanded interplanar distance of the heterostructure (1.104 nm) compared to that of pristine MoS 2 (0.615 nm). During HER tests, the heterostructure shows HER catalytic activity with overpotential of 180 mV at 10 mA cm À2 and a Tafel slope of 79 mV dec À1 in 0.5 M H 2 SO 4 .…”

“…b,c) Reproduced with permission. [25] Copyright 2020, American Chemical Society. The volcano curve from experimental measurement for some metal (111) plane d) without and e) with vdW correction.…”

Strategies to improve electrocatalytic and photocatalytic performance of two-dimensional materials for hydrogen evolution reaction

“…Graphene is 100 times harder than the hardest steel, and even harder than diamond. In graphene, each carbon atom has an unbound p-electron, which can move freely through the crystal at speeds as high as 1/300th of the speed of light, which endows graphene with good conductivity [72]. Due to its unique shape and thickness, graphene has outstanding optical, electrical and mechanical properties and important prospects in material science, micro-nano processing, energy, biomedicine, and drug delivery applications [73][74][75].…”

Van der Waals Heterostructures—Recent Progress in Electrode Materials for Clean Energy Applications

“…Therefore, vdW heterostructures rely heavily upon defects, such as atomic vacancies, heteroatom doping, and lattice deformation, to greatly enhance their ability as HER catalysts. Currently, water splitting systems are highly dependent upon precious metals, such as platinum [47].…”