2D/2D Heterostructured CdS/WS2 with Efficient Charge Separation Improving H2 Evolution under Visible Light Irradiation

TLDR: CdS/WS2 has great potential as a low-cost and highly efficient photocatalyst for water splitting and the lifetime and dynamics of photogenerated electrons were evaluated, indicating that WS2 works as an electron-trapping site and a cocatalyst to cause H2 evolution under visible light irradiation.

Abstract: Efficient water splitting for H2 evolution under visible light irradiation has attracted more attention for solving the global environmental and energy issues, but it is still a major challenge to develop an earth-abundant and efficient photocatalyst. Herein, we report two-dimensional (2D)/2D heterostructured CdS/WS2 (CdS/WS2), composed of nanosheet CdS (CdS) and nanosheet WS2 (WS2), as an efficient photocatalyst for H2 evolution. As a noble metal-free visible light-driven catalyst for H2 evolution, CdS/WS2 with 10 wt % WS2 exhibited the largest H2 evolution rate of 14.1 mmol g–1 h–1 under visible light irradiation to be 8 times larger than that of pure CdS. The lifetime and dynamics of photogenerated electrons were evaluated by femtosecond time-resolved diffuse reflectance spectroscopy, indicating that WS2 works as an electron-trapping site and a cocatalyst to cause H2 evolution under visible light irradiation. This work suggests that CdS/WS2 has great potential as a low-cost and highly efficient photoca...