Spatially separated bimetallic cocatalysts over hollow-structured TiO2 for photocatalytic hydrogen generation

Efficient charge separation and light harvesting of photocatalysts (e.g., TiO2) are the key issues to be considered in the design of solar-energy conversion systems. In particular, the charge separation of noble metal-decorated TiO2 materials could be greatly improved via decreasing the size of noble metal particles (NPs). Furthermore, designing specific morphologies such as hollow structures can improve light harvesting ability. Herein, a hybrid hollow TiO2 with spatially separated bimetals (Pd@TiO2@Au) was prepared, which demonstrated enhanced charge separation. By choosing zeolite as the sacrificial substrate, ultrasmall Pd NPs and Au NPs were decorated in the inner and outer shells of hollow TiO2, respectively. The separated bimetals could pull the photoexcited electrons away from the surface of TiO2 for more efficient charge separation. The as-prepared Pd@TiO2@Au catalyst exhibited a superior photocatalytic H2 evolution rate up to 272.3 μmol h−1, which was higher than most of the TiO2-based photocatalysts.