Synthesis and characterization of thermally stable large-pore mesoporous nanocrystalline anatase

Thermally stable mesoporous nanociystalline TiO2 with a pure anatase structure was obtained by sol-gel synthesis (in combination with hydrothermal treatment) using titanium tetrabutoxide and dibenzo-18-crown-6 as a structure-directing agent in presence of surfactant and/or La3+ ions additives. Nanocrystalline TiO2 demonstrates various textures with a well-defined spherical morphology (micro- and nanospheres), a crystallite size of no greater than 10 nm (XRD), and a narrow pore size distribution. Spherical particles of micrometer scale in the presence of La3+ ions do not form. TiO2 calcined (at 500 degrees C) after hydrothermal treatment (at 175 degrees C) has a significantly more developed porous structure as compared with TiO2 which was not treated hydrothermally. For example, specific surface area amounts 137 m(2) g(-1) and 69 m(2) g(-1), pore volume 0.98 cm(3) g(-1) and 0.21 cm(3) g(-1), pore diameter 17.5 nm and 12.5 nm respectively for samples hydrothermally treated and not treated. (C) 2013 Elsevier Inc. All rights reserved.