Hierarchical Heterostructure of ZnO@TiO2 Hollow Spheres for Highly Efficient Photocatalytic Hydrogen Evolution

The rational design and preparation of hierarchical nanoarchitectures are critical for enhanced photocatalytic hydrogen evolution reaction (HER). Herein, well-integrated hollow ZnO@TiO 2 heterojunctions were obtained by a simple hydrothermal method. This unique hierarchical heterostructure not only caused multiple reflections which enhances the light absorption but also improved the lifetime and transfer of photogenerated charge carriers due to the potential difference generated on the ZnO–TiO 2 interface. As a result, compared to bare ZnO and TiO 2 , the ZnO@TiO 2 composite photocatalyst exhibited higher hydrogen production rated up to 0.152 mmol h −1 g −1 under simulated solar light. In addition, highly repeated photostability was also observed on the ZnO@TiO 2 composite photocatalyst even after a continuous test for 30 h. It is expected that this low-cost, nontoxic, and readily available ZnO@TiO 2 catalyst could exhibit promising potential in photocatalytic H 2 to meet the future fuel needs.