Enhanced visible light photocatalytic hydrogen production activity of CuS/ZnS nanoflower spheres

Abstract

A novel visible-light-driven photocatalyst CuS/ZnS with nanoflower architectures has been synthesized by a simple hydrothermal method and a successive cation exchange treatment. The visible light photocatalytic hydrogen production activity was estimated from a mixed Na₂S and Na₂SO₃ aqueous solution. The experimental results reveal that the photocatalytic performance of ZnS nanomaterials can be enhanced dramatically with the deposition of a small percentage of CuS. When loading a 1.97 mol% CuS content, the as-prepared CuS/ZnS sample reaches an optimal hydrogen production rate of 5152 μmol h⁻¹ g⁻¹ under visible light and an apparent quantum efficiency of 26.2% at 420 nm (without the assistance of a Pt co-catalyst). The high photocatalytic performances are attributed to the low energy level provided by the deposited CuS on the ZnS surface, which can be activated under visible light. Furthermore, the interpolar electric field (IPEF) existing in ZnS nano-architectures can also promote the efficient separation of the photogenerated charge carriers and thus enhance the hydrogen production activity.