Efficient Degradation of Methylene Blue over Two-Dimensional Au/TiO2 Nanosheet Films with Overlapped Light Harvesting Nanostructures

Two-dimensional TiO2 nanosheet films with visible light trapping nanostructures were successfully fabricated by alkali hydrothermal reaction using Ti sheet as precursor. Metallic Au nanoparticles (NPs) were then deposited on the surface of TiO2 film through a microwave-assisted reduction process. The investigations reveal that the localized surface plasmon resonance (LSPR) of Au NPs is greatly enhanced by the overlapped light harvesting nanostructures between TiO2 film and Au NPs, resulting in an enhanced LSPR-absorption with two peaks at 389 nm and 540 nm. The photocatalytic performance of the samples was evaluated by degradation of methylene blue (MB) as a model pollutant. The experimental results indicate that the photocatalytic performance of TiO2 is greatly promoted by a synergetic effect between the overlapped light harvesting nanostructures and the improved charge carrier separation processes. The MB degradation over the optimal sample is much faster than that of pure TiO2 film by a factor of 3.0 and 5.7 under UV light and UV + visible light irradiation, respectively. This study provides a simple strategy to develop film-shaped plasmonic photocatalysts with high efficiency.