<scp>MoS₂</scp>–<scp>WS₂</scp> Heterostructures with Vertical Nanosheets for Enhanced Photocatalytic Hydrogen Generation through Morphology‐Controlled Chemical Vapor Deposition

Constructing a nanostructure that combines abundant active edge sites with a well‐designed heterostructure is an effective strategy for enhancing photocatalytic hydrogen generation. However, controllable approaches for creating heterostructures based on vertically standing transition metal dichalcogenide (TMD) nanosheets remain insufficient despite their potential for efficient hydrogen production. In this paper, we present efficient photocatalysts featuring heterojunctions composed of vertically grown TMD (MoS 2 and WS 2 ) nanosheets. These structures (WS 2 , MoS 2 , and MoS 2 /WS 2 heterostructure) were fabricated using a controllable metal–organic chemical vapor deposition method, which expanded the surface area and facilitated effective photocatalytic hydrogen evolution. The vertical MoS 2 /WS 2 heterostructures demonstrated significantly enhanced hydrogen generation, driven by the synergistic effects of improved light absorption, a large specific surface area, and appropriately arranged staggered heterojunctions. Furthermore, the photocatalytic activity was considerably influenced by the size and density of the vertical nanosheets. Consequently, the nanosheet size‐tailored MoS 2 /WS 2 heterostructure achieved a photocatalytic hydrogen generation rate (454.2 μmol h −1 cm −2 ), which is 2.02 times and 2.19 times higher than that of WS 2 (225.6 μmol h −1 cm −2 ) and MoS 2 (207.2 μmol h −1 cm −2 ). Hence, the proposed strategy can be used to design staggered heterojunctions with edge‐rich nanosheets for photocatalytic applications.