Revisiting Pressure-Induced Transitions in Mesoporous Anatase TiO2

Mesoporous materials may be considered as the negative image of a collection of nanoparticles. In both cases, the large surface area induces an increase of the system energy. Pressure-induced phase transitions are used to study the differences between mesoporous TiO2 and a collection of TiO2 nanoparticles. The synthesis and characterization of mesoporous TiO2 with a nanosponge-like structure are presented, and the inputs of different spectroscopic techniques (terahertz, Brillouin, and Raman) are highlighted. The results show that the phase stability of mesoporous TiO2 under pressure is very similar to that observed in nanoparticles.