Sol-gel route to synthesis of microporous ceramic membranes: Thermal stability of TiO2-ZrO2 mixed oxides

In this paper concerning the synthesis of microporous ceramic membranes, we focus on the preparation and thermal stability of unsupported microporous TiO2-ZrO2 mixed-oxide membranes. It has been observed that, by adding up to 20% ZrO2 into TiO2 or up to 10% TiO2 into ZrO2, these microporous membranes display improved thermal stability. They can be fired up to 500 °C for 0.5 h without closing micropores. However, membranes containing almost equal percentages of each component have lost microporous features and have low surface areas and low porosities. A phase diagram of a two-component TiO2-ZrO2 mixed-oxide membrane has been prepared based on DTA and X-ray diffraction data in order to better understand the microstructure changes upon firing.