Synthesis and characterization of mesoporous titania and silica–titania materials by urea templated sol–gel reactions

Mesoporous titania and mesoporous silica–titania materials have been successfully synthesized by using organic compound urea as template (or pore-forming agent) via sol–gel reactions of tetrabutyl titanate alone and with tetraethyl orthosilicate, respectively, followed by removing the urea by extraction with water. The pore parameters and morphology were characterized by N2 adsorption–desorption measurement, powder X-ray diffraction and transmission electron microscopy. The pore diameters of synthesized titania, up to 5.5 nm, were larger than those mesoporous titania materials prepared by other nonsurfactant compounds reported previously by us. The pore diameters of silica–titania materials decreased with the increase of Si/Ti ratio from 1/100 to 2/1 under the same template concentration.