Preparation and characterization of photocatalytic titania–alumina composite membranes by sol–gel methods

Titania–alumina composite membranes containing 10 and 20 mol% alumina were prepared by two different sol–gel methods; co-hydrolysis and separately peptized. The samples were characterized by different techniques. XRD results showed that for the composite membranes the anatase to rutile transformation temperature was increased by 200 and 300 °C. According to specific surface area results, alumina effectively increased the specific surface area of composite membranes compared to pure titania membranes. Microstructure of composite supported membranes was considered by scanning electron microscopy and showed a crack-free layer with 1 μm thickness. The photocatalytic activity of composite samples showed that alumina addition up to an optimum amount can slightly affect the photocatalytic activity of titania.