CHARACTERIZATION OF PT-SN BIMETALLIC CATALYSTS SUPPORTED ON ALUMINA AND NIOBIA

Alumina and niobia Pt-Sn supported bimetallic catalysts were characterized by TPR, hydrogen chemisorption and cyclohexane dehydrogenation. The TPR profiles of niobia supported Pt-Sn catalysts showed the presence of different precursors from the ones obtained on alumina. Furthermore, the hydrogen uptakes indicated that the amount of metallic tin formed in the niobia supported catalysts was higher than in the alumina supported catalysts. After reduction at 773 K, the platinum/niobia catalyst displayed a strong metal-support interaction (SMSI) effect, with the creation of new interfacial active sites. The addition of a small tin content led to a suppression of the SMSI. Increasing the amount of tin, however, induced a marked poisoning of the platinum.