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.