Influence of drying technique on silicon insertion into γ-alumina and consequences for the homogeneity and thermal stability of silica–alumina aquagels

Abstract

Si-doped alumina gels of nominal composition (Al₂O₃)_0.88–(SiO₂)_0.12 have been synthesised in aqueous media and dried under different conditions in order to obtain xerogel (drying at 120 °C) or aerogel (supercritical CO₂ drying) forms; after heating at 1200 °C for 5 h, the aerogel samples are more homogenous and retain a better specific surface area (>100 m² g⁻¹) than the xerogel samples.