Synthesis of very small TiO2 nanocrystals in a room-temperature ionic liquid and their self-assembly toward mesoporous spherical aggregates.

In this Communication, we describe the synthesis of 2-3 nm sized titania nanocrystals in a room-temperature ionic liquid under mild conditions and their self-assembly toward mesoporous TiO2 spheres. The resulting structures combine the convenient handling of larger spheres with a considerable high surface area and narrow pore size distribution and are expected to have potential in solar energy conversion, catalysis, and optoelectronic devices.