Efficient charge separation can promote photocatalysis of semiconductors. Herein, a hollow-structured TiO2 sphere decorated with spatially separated bifunctional cocatalysts was designed, which exhibited enhanced photocatalytic hydrogen generation. Ultrasmall-sized MOx (M = Pd, Co, Ni, or Cu) nanoparticles (NPs) were first introduced into a zeolite via confinement synthesis, and then, hollow TiO2 was fabricated by using the zeolite as a sacrificial template forming MOx@TiO2. Finally, Pt NPs were decorated on the outer shell, giving rise to MOx@TiO2@Pt, in which the MOx NPs and Pt NPs acted as hole capturers and electron sinks, respectively. Thanks to the enhanced light harvesting of the hollow structure and improved charge separation induced by the smaller-sized cocatalysts as well as spatially separated bifunctional cocatalysts, the as-prepared PdOx@TiO2@Pt catalyst exhibited a superior photocatalytic hydrogen-generation property (0.45 mmol h–1). This work demonstrates the advantage of the spatially separated bifunctional cocatalysts in enhancing the photocatalytic properties of semiconductors.
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.
危险品化学品经营许可证（带存储）