화학공학소재연구정보센터
Powder Technology, Vol.107, No.1-2, 118-122, 2000
Titania-induced changes of silica texture upon moderate heating
Induced changes in the texture of silica gel due to physically mixed titania (15-85 mol%) upon heating at 300 degrees C or 600 degrees C in air are inspected through a detailed pore structure analysis using adsorption of N-2 at 77 K. The decreases in surface area and pore volume with the corresponding variations in the average hydraulic pore radius of silica recorded at both heating temperatures are attributed to the disturbance of the normal conditions of silica dehydration-dehydroxylation due to presence of titania. Water desorbed from titania upon heating up to 300 degrees C alters the arrangement of siloxane links that form between primary particles of silica upon dehydroxylation. The active Lewis sites of titania surface that develop in the course of heating up to 600"C disturb the usual equilibrium between surface and bulk water of silica.