Characterization and Catalytic Behaviour of Co 3 (PO 4 ) 2 –AlPO 4 Catalysts

Abstract

Co₃(PO₄)₂, AlPO₄ and the binary system Co₃(PO₄)₂-AlPO₄ with different compositions were prepared by the coprecipitation method. The structural properties of these samples were determined using XRD, DTA and FT-IR techniques. The textural properties were determined from the adsorption of nitrogen at 77 K. The surface acidity was measured by a calorimetric titration method. The samples were tested as catalysts in the dehydration of ethanol and isopropanol using a pulse microcatalytic technique. The data obtained from XRD and FT-IR indicate the amorphous structures of the prepared catalysts. An increase in Co₃(PO₄)₂ content led to a decrease in the surface area and in the total pore volume and an increase in the mean pore radius. The surface acidity of the catalyst depends on the chemical composition; the surface acidity increased with an increase in the AlPO₄ content. The dehydration temperature and the distribution of acid sites are important parameters in determining the selectivity and activity of the catalyst.