MoSe2 Nanosheet Array with Layered MoS2 Heterostructures for Superior Hydrogen Evolution and Lithium Storage Performance.

Engineering heterostructures of transition metal disulfides through low-cost and high-yield methods instead of using conventional deposition techniques still have great challenges. Herein, we present a conveniently operated and low-energy-consumption solution-processed strategy for the preparation of heterostructures of MoSe2 nanosheet array on layered MoS2, among which the two-dimensional MoS2 surface is uniformly covered with high-density arrays of vertically aligned MoSe2. The unique compositional and structural features of the MoS2-MoSe2 heterostructures not only provide more exposed active sites for sequent electrochemical process, but also facilitate the ion transfer due to the open porous space within the nanosheet array serving as well-defined ionic reservoirs. As a proof of concept, the MoS2-MoSe2 heterostructures serve as promising bifunctional electrodes for both energy conversions and storages, which exhibit an active and acid-stable activity for catalyzing the hydrogen evolution reaction, high specific capacity of 728 F g-1 at 0.1 A g-1, and excellent durability with a remained capacity as high as 676 mA h g-1 after 200 cycles.