Fabrication and Enhanced Photoactivities of Plasmonic Ag/TiO₂ Nano-Flower Films.

Titania nano-flower films were in this study decorated with silver nanoparticles (Ag/TiO₂ NFFs) and fabricated through a facile hydrothermal route, followed by a microwave-assisted reduction process. The investigations indicated that the Ag nanoparticles were deposited evenly on the anatase TiO₂ film, forming a heterogeneous structure. The prepared composites exhibited excellent visible light harvesting ability due to the light-scattering TiO₂ nanostructures and localized surface plasmon resonance (LSPR) of Ag NPs. In addition, a lower recombination probability for the photoexcited charge carriers was observed. These experimental results demonstrated that the Ag/TiO₂ NFFs possessed obviously enhanced photocatalytic activities for methyl orange (MO) degradation in comparison with pure TiO₂ NFFs, and the corresponding degradation rate was 3.5 times as much as that of pure TiO₂ NFFs. This enhancement arose from the positive synergetic effect between the charge separation behavior and LSPR effect from the Ag nanoparticles. The results from the present study demonstrate that the visible light capturing ability for the TiO₂-based semiconductors can be achieved through rational design of their nanostructures or through the LSPR effect originating from the plasmonic nanoparticles. This work also offers a facile approach for developing film photocatalysts with high efficiency.