Abstract
In this study, we for the first time came up with a facile approach to fabricate hierarchically porous nano-crystalline monolithic magnesium titanates (MgTi2O5/MgTiO3) by impregnating magnesium chloride into hierarchically porous TiO2 monolith in a solution containing urea followed by appropriate heat-treatment. The formation of porous MgTi2O5/MgTiO3 monolithic materials took place by the solid-state reaction between original TiO2 networks and precipitated MgCO3. The MgCO3 is precipitated within the TiO2 wet gel by the reaction between impregnated Mg2+ and CO2, which is produced by hydrolysis and decarbonation of chelating agent in the TiO2 wet gels and by the hydrolysis of urea at 60°C. The resultant porous magnesium titanates retained narrow macropore size distribution centered at the diameter ∼1 µm. These porous monoliths produced by impregnation, a facile and the low-cost method, are expected to open various engineering applications owing to the low thermal expansion coefficients and high chemical and physical stabilities.
