DETERMINATION OF THE ACCESSIBLE METAL FRACTION AND THE METAL-PARTICLE SIZE ON COKED PT/AL2O3-CL CATALYSTS

The chemisorption of H//2, O//2 and CO, and the H//2-O//2 titration method were used for determining the accessible metal fraction of coked Pt/Al//2O//3 reforming catalysts. Several Pt/Al//2O//3 catalysts with different metal loading and metal particle size were employed. A high pressure run using naphtha as feed was performed to coke the samples. Gas uptakes were compared with the catalytic activity of benzene hydrogenation. It was found that the irreversible CO adsorption may be taken as a measure of the accessible metal fraction of coked Pt/Al//2O//3 catalysts; both oxygen and hydrogen uptakes led to wrong results.