DEACTIVATION CHARACTERISTICS IN N-HEPTANE REFORMING REACTION CATALYZED OVER SMALL PT, IR AND PT-IR BIMETALLIC CLUSTERS IN NAY

Abstract

The deactivation characteristics of highly dispersed (about 1 nm) Pt, Ir and Pt-Ir bimetallic clusters in NaY were studied by hydrogen chemisorption, coke analysis and temperature programmed oxidation of used catalyst in n-heptane reforming reaction. As the Ir content was increased, the amount of coke decreased. Most of coke was located around the metal cluster and this coke decreased the selectivity of dehydrocyclization in n-heptane reaction. The higher activity and more improved activity maintenance of Pt-Ir/NaY bimetallic catalysts than those of Pt/NaY are related to the less amount of coke formation.