Sol–Gel Synthesis of Alumina–Titania Nanostructure Membrane: Preparation and Characterization

In the present paper, the preparation and characterization of porous alumina–titania nanostructure membrane is described. The membrane layers consisted of an α-alumina membrane support, which was dip-coated with a composite alumina–titania top layer prepared in a sol–gel process. Thermogravimetric analysis showed that drying progress of the membrane layer is completed at about 560 °C. Scanning electron microscopy analysis displayed a smooth and defect-free layer of alumina–titania membrane after calcination at 600 °C. X-ray diffraction analysis showed the formation of gamma and orthorhombic alumina, brookite titania, and aluminium titanate (Al₂TiO₅) after the calcination step. Transmission electron microscopy analysis showed that the alumina–titania composite particle size was almost below 40 nm. The Brunauer–Emmet–Teller (BET) surface area, average pore size, and thickness of the membrane top layer were determined to be 292 m²/g, 2.2 nm, and 4 μm, respectively.