Room temperature synthesis of mesoporous aggregates of anatase TiO2 nanoparticles

The controlled hydrolysis reaction of titanium tetrabutoxide in presence of acetic acid in isopropanol, i.e. in non-aqueous media was adopted in the present work for the synthesis of nanocrystalline titania followed by aging at ambient conditions for longer duration. The powder XRD shows that the as-dried precursor (without any aging) is non-crystalline in nature. However, room temperature aging for longer duration >120 days not only helped to develop crystallinity in TiO2 nanoparticles but also led to the formation of their self-assembly towards mesoporous aggregates creating sponge like TiO2 nano-structure having high surface area ∼250 m2 g−1 and narrow pore size distribution of 4–5 nm. TEM observations revealed the generation of spherical TiO2 nanoparticles (4–5 nm) assembled to form stable spongy scaffold having porous network structure with pore size 5–6 nm. Also, presence of a pronounced hysteresis loop in BET isotherm is indicative of a 3D-intersection network of the pores of size 4–5 nm. Further heat-treatment to the aged precursor at 400 °C/2 h in air modify pore network structure due to sintering of TiO2 particles as is observed in TEM studies and lowering thereby the surface area to 125 m2 g−1.