Facile Preparation of Hierarchically Porous TiO 2 Monoliths

Monolithic titania (TiO 2 ) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO 2 gels obtained possess well‐defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO 2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO 2 particles comprising TiO 2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO 2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.