A facile method to fabricate monolithic alumina-silica aerogels with high surface areas and good mechanical properties

In this study, monolithic alumina-silica aerogels with high surface areas and good mechanical properties were synthesized via a facile sol-gel method without solvent exchange. Furthermore, surface areas, microstructures (up to 1300 degrees C), and mechanical properties of the prepared alumina-silica aerogels were investigated. The sintering and phase transformations of metastable alumina nanoparticles are suppressed owing to the uniformly distributed Si in the alumina-silica aerogels; therefore, the alumina-silica aerogels can maintain much higher specific surface areas after being calcined at 800 degrees C (575.5 m(2)/g), 1000 degrees C (443.2 m(2)/g), and 1200 degrees C (120.6 m(2)/ g) compared to pristine alumina aerogels. In addition, the prepared high surface area alumina-silica aerogels show considerably higher strengths than those obtained in previous works. The compressive stress (3 % strain) and elastic modulus of the alumina-silica aerogels reached 1.78 and 65.6 MPa, respectively. The reported alumina-silica aerogels in this study can be good candidates as high-temperature thermal insulators and catalysts.