In2Se3/CdS nanocomposites as high efficiency photocatalysts for hydrogen production under visible light irradiation

Abstract

Hydrogen energy is an important clean energy. Using visible light to produce hydrogen by semiconductor photocatalysts is one of the current research hotspots. In this work, In2Se3/CdS nanocomposite photocatalysts with different mass content of CdS are prepared. The In2Se3/CdS photocatalyst with 85.25% CdS mass content exhibits the optimal photocatalytic hydrogen evolution activity (1.632 mmol g−1 h−1), which is much higher than that of CdS (0.715 mmol g−1 h−1) and In2Se3 (trace). Moreover, the In2Se3/CdS photocatalyst still maintains a high hydrogen evolution rate after five cycles. The high photocatalytic activity and stability of the In2Se3/CdS nanocomposite is due to the formation of heterojunction between In2Se3 and CdS. The existence of heterojunction is confirmed by high resolution transmission electron microscopy image and X-ray photoelectron spectra. Theoretical calculations and experimental results indicate that the electron transfer route at the heterojunction is step-scheme. The step-scheme helps the separation of photogenerated electrons and holes, and maximize the hydrogen evolution activity. This work provides a high efficiency step-scheme photocatalyst for hydrogen production.