Bimetallic particle formation in Pt-Re/Al2O3 reforming catalysts revealed by energy-dispersive X-ray spectrometry in the analytical electron microscope

摘要

The metal function of a commercial 0.3-0.3 wt% Pt-Re/Al2O3 catalyst was studied by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectrometry (EDX). Evidence for platinum-rhenium bimetallic particle formation in the reduced catalyst has been established. The degree of Pt-Re interaction is highly dependent on the conditions 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 decomposition, sintering, and a low degree of Pt-Re interaction. The part of the rhenium not associated with platinum is possibly distributed on the surface of the alumina support as submicroscopic particles. (C) 1998 Academic Press. [References: 18]