BIMETALLIC PARTICLE FORMATION IN PT-RE AL2O3 REFORMING CATALYSTS REVEALED BY ENERGY-DISPERSIVE X-RAY SPECTROMETRY IN THE ANALYTICAL ELECTRON-MICROSCOPE/

The metal function of a commercial 0.3-0.3 wt% Pt-Re/Al2O3 catalyst wa s studied by scanning transmission electron microscopy (STEM) and ener gy dispersive X-ray spectrometry (EDX). Evidence for platinum-rhenium bimetallic particle formation in the reduced catalyst has been establi shed. The degree of Pt-Re interaction is highly dependent on the condi tions employed during catalyst pretreatment. The highest degree of Pt- Re interaction is obtained if the catalyst is not dehydrated prior to reduction. High-temperature N-2 treatment causes platinum oxide decomp osition, sintering, and a low degree of Pt-Re interaction. The part of the rhenium not associated with platinum is possibly distributed on t he surface of the alumina support as submicroscopic particles. (C) 199 8 Academic Press.