THE NATURE OF RUTHENIUM SULFIDE CLUSTERS ENCAGED IN A Y-ZEOLITE

Catalysts of ruthenium sulfide supported in a dealuminated KY zeolite were prepared by ion exchange and subsequent sulfidation using several atmospheres containing sulfur. They were characterized by means of HR EM, EDX, TPR, and EXAFS. The activity for the tetralin hydrogenation, carried out in presence of large amounts of H2S (1.85%), was very high and roughly 300 times the activity (expressed per metal atom) of an i ndustrial NiMo/Al2O3 hydrotreating catalyst. A simple modeling of the results obtained by the physicochemical techniques suggests that the a ctive phase consists of clusters of less than 50 ruthenium atoms of a ruthenium sulfide-like phase with very small domains of ruthenium meta l. (C) 1997 Academic Press, Inc.