Few-layer WSe2 nanosheets as an efficient cocatalyst for improved photocatalytic hydrogen evolution over Zn0.1Cd0.9S nanorods.

• Few-layer WSe 2 nanosheets are synthesized via a facile colloidal method. • 2D WSe 2 as a new cocatalyst significantly improves photocatalytic hydrogen production. • A hydrogen production rate of 147.32 mmol/(g·h) with an AQY of 39.5% is achieved. • Femtosecond transient absorption proves the fast electron transfer to WSe 2 cocatalyst. Efficient and low-cost cocatalysts play a critical role in improving the efficiency of photocatalysts. Herein, few-layer WSe 2 nanosheets were prepared via a facile colloidal method and applied as a new cocatalyst to improve the photocatalytic performance of Zn 0.1 Cd 0.9 S nanorods. It was discovered that WSe 2 decorated Zn 0.1 Cd 0.9 S nanorods showed enhanced photocatalytic hydrogen production compared with pristine Zn 0.1 Cd 0.9 S nanorods. A highest hydrogen generation rate of 147.32 mmol/(g·h) was obtained when the weight ratio of WSe 2 to Zn 0.1 Cd 0.9 S was optimized to 10 wt%, which corresponded to an apparent quantum yield of 39.5% at 425 nm. The charge transfer kinetics were studied by femtosecond transient absorption spectroscopy. Direct and fast electron transfer from Zn 0.1 Cd 0.9 S to WSe 2 was demonstrated, which was crucial to the dramatic improvement of photocatalytic activity. This work offers us another efficient two-dimensional cocatalyst for photocatalytic hydrogen generation and provides some new insights about charge transfer in hybrid catalysts. [ABSTRACT FROM AUTHOR]