Bimetallic Pt-Pd/silica-alumina hydrotreating catalysts - Part I: Physicochemical characterization

► Pt-Pd catalysts supported on silica and amorphous silica-alumina were characterized. ► Pt-Pd clusters form with Pt-rich core and Pd-rich surface. ► Electrons are transferred from Pt to Pd in the Pt-Pd nanoclusters. ► The alumina content of the support affects the morphology of the Pt-Pd nanoclusters.