Studies on PO43-/ZrO2 - II. Effect of phosphate concentration and activation temperature on the catalytic properties of zirconia

The effect of activation temperature and phosphate concentration on the cat alytic properties of phosphated zirconia (PO43-/ZrO2) has been described. X RD patterns show that phosphate stabilizes the tetragonal phase of ZrO2 up to 1000 degrees C but the crystallization temperature is delayed with incre ases in the concentration of phosphate. Surface area and surface acidity of the samples increase with increases in the phosphate up to a certain conce ntration and decrease with further increases. The cumene cracking/ dehydrog enation and 2-propanol conversion reactions are carried out to evaluate the catalytic properties of the samples. The nature of sites present on the sa mples has been determined and discussed by correlation of the concentration of phosphate, activation temperature, and activity and selectivity to a pa rticular product. Among the 400, 500, and 600 degrees C activated samples, the 500 degrees C sample has shown maximum activity toward the above reacti ons. (C) 2000 Academic Press.