Silica-alumina catalytic materials: A critical review

The applications of silica-aluminas in industrial catalytic processes are briefly reviewed. The literature data on the surface chemistry and structural chemistry of silica-aluminas are summarized. The Al-stuffed amorphous silica model is proposed for fully amorphous materials, and described. The reasons for the versatility of these materials as acid or acido-basic catalysts as well as tunable supports for metal and sulphide catalysts are also discussed.