Template-free co-assembly of preformed Au and TiO2 nanoparticles into multicomponent 3D aerogels

The self-assembly properties of titania nanoparticles, which are strong enough to bridge several lengths scales, make it possible to use them as building blocks for aerogels. Controlled by their surface functionalization, the nanoparticles undergo an oriented attachment process during gelation, building up a 3-dimensional macroporous network. The presence of other nanoparticles in the initial reaction mixture results in the formation of multicomponent aerogels, offering a flexible tool to vary the composition of the gels and thus the chemical properties. Exemplarily this is shown by the co-assembly of titania with gold nanoparticles, leading to a Au–TiO2 composite aerogel with enhanced photocatalytic activity under visible light.