Titanium Dioxide Photonic Crystals with Enhanced Photocatalytic Activity: Matching Photonic Band Gaps of TiO2 to the Absorption Peaks of Dyes

Photonic crystals have attracted extensive interest for the potential applications in manipulating light by nontraditional ways based on photonic band structure concepts. In this paper, 3D inverse-opal TiO2 photonic crystals (TiO2-PCs) with designed photonic band gaps are prepared. It is worth noting that when the photonic band gaps of the TiO2-PCs are matched with the absorption peaks of the dyes (methyl orange, rhodamine B, and methylene blue), the photocatalytic activity of the corresponding sample is improved under simulated solar light (320 nm < lambda < 800 nm) and visible light (420 nm < lambda < 800 nm) irradiation. The enhancement could be attributed to the intensified dye sensitization as a result of slow photon effect on the edges of the photonic band gaps. Furthermore, the TiO2-PCs exhibit much higher photocatalytic activity and stability than TiO2 nanoparticle film. It is believed that the presence of inverse opal structure plays an essential role in affecting the dye sensitization and photoreactivity, which could provide valuable information on the design of photocatalysts and set the foundation for the future environmental and energy technologies.