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

Efficient and low-cost cocatalysts play a critical role in improving the efficiency of photocatalysts. Herein, few-layer WSe2 nanosheets were prepared via a facile colloidal method and applied as a new cocatalyst to improve the photocatalytic performance of Zn0.1Cd0.9S nanorods. It was discovered that WSe2 decorated Zn0.1Cd0.9S nanorods showed enhanced photocatalytic hydrogen production compared with pristine Zn0.1Cd0.9S nanorods. A highest hydrogen generation rate of 147.32 mmol/(g·h) was obtained when the weight ratio of WSe2 to Zn0.1Cd0.9S 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 Zn0.1Cd0.9S to WSe2 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.