Synthesis and textural properties of unsupported and supported rutile (TiO2) membranes

Two approaches were postulated for improving the stability of the porous texture of titania membranes: retarding the phase transformation and grain growth; and avoiding the phase transformation. Based on the second approach, rutile membranes were made directly from a rutile sol, prepared by the precipitation of titania on SnO2 nuclei. The rutile membranes were stable up to 800 C, with a porosity of about 40%, whereas normal titania membranes (starting with anatase) show very little porosity above 600 C. Alumina substitution retards grain growth and pore growth at 850 C for unsupported as well as supported membranes. 29 refs.