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

Abstract

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