TRANSITION-METAL PROMOTED AMORPHOUS AIPO(4) CATALYSTS .1. ACID-BASE AND TEXTURAL PROPERTIES

Transition metal promoted amorphous aluminium phosphate (M(0.05)Al(0.9 5)PO(4)) samples were prepared (by precipitation and calcination) and characterized by chemical analysis, TG, XRD, nitrogen adsorption-desor ption isotherms, surface acidic-basic sites, and oxidizing-reducing si tes, Chemical analysis shows that the P/(Al + M) ratio in all the case s is slightly less than 1. Nitrogen adsorption-desorption studies at l iquid nitrogen temperature shows that all the samples have high specif ic surfaces and possess both micro as well as meso pores in the range 2.6 to 3.8 mm, The acidic-basic and oxidizing-reducing sites on the su rface of amorphous aluminium phosphate increased with the addition of transition metals. Surface area, acid-base, and oxidizing-reducing pro perties increased slightly with an increase in calcination temperature up to 600 degrees C, then decreased to low values at 800 degrees C. ( C) 1996 Academic Press, Inc.