Controlling nanoparticle placement in Au/TiO 2 inverse opal photocatalysts.

Gold nanoparticle-loaded titania (Au/TiO 2 ) inverse opals are highly ordered three-dimensional photonic structures with enhanced photocatalytic properties. However, fine control over the placement of the Au nanoparticles in the inverse opal structures remains challenging with traditional preparative methods. Here, we present a multi-component co-assembly strategy to prepare high-quality Au/TiO 2 inverse opal films in which Au nanoparticles are either located on, or inside the TiO 2 matrix, as verified using electron tomography. We report that Au nanoparticles embedded in the TiO 2 support exhibit enhanced thermal and mechanical stability compared to non-embedded nanoparticles that are more prone to both leaching and sintering.