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The successful designing of low‐cost and highly active electrocatalytic materials from earth‐abundant elements are favorable for the large scale production of hydrogen from water splitting. Herein, the controllable sandwiching of reduced graphene oxide (RGO) in hierarchical defect‐rich MoS2 ultrathin nanosheets (MoSGMoS) with vertical alignment and expanded interlayer spacing is synthesized by hydrothermal method. The MoSGMoS product exhibits outstanding electrocatalytic activity for hydrogen evolution reaction (HER) with an onset overpotential of 24.3 mV, low overpotentials of 72 mV at 10 mA cm−2 and 384 mV at 1300 mA cm−2, a small Tafel slope of 44.7 mV decade−1, large exchange current density of 0.67 mA cm−2, and high durability in H2SO4 solution. The HER performance of the MoSGMoS catalyst is much better than most of the reported MoS2‐based catalysts, especially in terms of onset overpotential and cathodic current density. The synergistic effect between defect‐rich MoS2 ultrathin nanosheets with hierarchical structure, vertical alignment and expanded interlayer spacing, and conductive RGO is responsible for the outstanding HER activity. This method may open a new way to grow hierarchical MoS2 nanosheets on carbonaceous materials for enhanced hydrogen production from water splitting.

electric vehicle industry puts forward higher requirements on the energy density and power density of commercial LIBs. [1,2] Current commercial LIBs commonly use graphite-based anodes, which suffer from a low theoretical capacity (372 mAh g −1 ) and relatively slow lithium-ion insertion-desertion kinetics, and thus cannot meet future market requirement for high energy density and power performance. [3,4] Therefore, it is of considerable significance to develop highperformance anode materials to replace the currently widely used graphite-based materials. Among multifarious potential anode materials, transition metal oxides (TMOs) such as Fe 2 O 3 , [5,6] Co 3 O 4 , [7,8] NiO, [9] Ni x Zn y Co 3−x−y , [10] MnO [11,12] as well as their composites, [13][14][15] which take place in conversion reaction with Li + , have many advantages in terms of high theoretical capacity, low acquisition cost, and safety. [16,17] However, there are still some problems to be solved before TMOs can be used as practical LIBs anodes, including huge volume expansion during the lithiation process, low electronic and ionic conductivity, and severe electrolyte decomposition during cycling. [18,19] As we know, poor conductivity of the material will lead to lower capacity release, vast volume expansion will cause rapid capacity decay, and continuous electrolyte decomposition will bring about an abnormal capacity variation. [20,21] It has been found that the nanoengineering and structural engineering design, such as constructing nanoporous [22,23] and hollow [24,25] structures, can shorten the diffusion length of Li + and offer buffer space for volume expansion, and thus improve the capacity release and cycling stability of TMOs anodes. Nevertheless, the highly porous design with a large specific surface area may aggravate side reaction of electrolyte and ultimately result in a significant initial irreversible capacity, [7,8] and hollow structure with low packing density can cause low volumetric energy density. To make better utilization of the inner hollow cavity, core-shell or multi-shell structures are highly desired. [26][27][28] However, construction of core-shell or multi-shell structures is usually a complex and tedious process. On the other hand, the introduction of graphene by in situ or ex situ methods has been proved to be highly effective in improving the conductivity and cyclic life of the TMOs-based Transition metal oxides (TMOs) are promising anode materials for next-generation lithium-ion batteries (LIBs). Nevertheless, their poor electronic and ionic conductivity as well as huge volume change leads to low capacity release and rapid capacity decay. Herein, a reduced graphene oxide (rGO)-encapsulated TMOs strategy is developed to address the above problems. The Co 3 O 4 -CoFe 2 O 4 @rGO composites with rGO sheets-encapsulated Co 3 O 4 -CoFe 2 O 4 microcubes are successfully constructed through a simple metal-organic frameworks precursor route, in which Co[Fe(CN) 5 NO] microcubes are in situ coated by graphene oxide sheets, followe...