Metal-support effects of platinum supported on zinc aluminate

Nanocrystalline and nanoporous zinc aluminate spinel ZnAl2O4 was obtained o n hydrothermal conditions at a low temperature. ZrAl2O4 support was impregn ated by an incipient wetness technique using aqueous solutions of H2PtCl6 t o obtain platinum contents up to 1 wt%, and then reduced with combustion ga ses at 673 K. After heat treatment in air or hydrogen how at temperatures u p to 1473 K, the Pt/ZnAl2O4 system was characterised by the powder X-ray di ffraction, high resolution transmission electron microscopy and textural st udies (specific surface area and pore size distribution), and tested in tot al oxidation of iso-butene. It was found that platinum on zinc aluminate mi ght strongly interact with the support in the reducing atmosphere, leading to a platinum-zinc alloy formation. The presence of Pt-Zn alloys on the sur face of a catalyst leads to a reversible deactivation of Pt/ZnAl2O4 catalys t. (C) 2001 Elsevier Science Ltd. All rights reserved.