High-yield exfoliation of MoS2 (WS2) monolayers towards efficient photocatalytic hydrogen evolution

Monolayer MoS2 (WS2) nanosheets have triggered tremendous interest due to their fascinating unique properties, but high-yield production of single-layer MoS2 (WS2) still remains an enormous challenge and of great interest. Herein, we report a facile efficient partial etching strategy to tailor thickness and lateral size of MoS2 (WS2) so as to increase the fraction of edges, which remarkably enhanced the yield of monolayer MoS2 (20%) and WS2 (12%) nanosheets by liquid phase exfoliation. As a proof of concept, the exfoliated monolayer MoS2 (WS2) nanosheets were applied as the cocatalysts for photocatalytic hydrogen evolution. Notably, the optimized hybrids exhibit excellent hydrogen evolution performance, which are over 31-fold (MoS2/CdS) and 47-fold (WS2/CdS) higher that of bare CdS counterpart, respectively. Hence, this work not only may pave the new way for the high-yield production of transition-metal dichalcogenides monolayers by liquid phase exfoliation, but also provide the possibility for the further efficiently exfoliating other two-dimension layered materials.