Controlling nanoparticle placement in Au/TiO₂ inverse opal photocatalysts

Gold nanoparticle-loaded titania (Au/TiO₂) 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/TiO₂ inverse opal films in which Au nanoparticles are either located on, or inside the TiO₂ matrix, as verified using electron tomography. We report that Au nanoparticles embedded in the TiO₂ support exhibit enhanced thermal and mechanical stability compared to non-embedded nanoparticles that are more prone to both leaching and sintering.