Preparation of Pt°/MCM-41: effect of drying on MCM-41 structure and Pt° dispersion
Résumé
Pt°/MCM-41 catalysts were prepared by electrostatic adsorption of Pt(NH3)42+ at pH=8, followed by calcination under O2 and reduction. This procedure allows to prepare highly dispersed Pt° nanoparticles (D>76%), but has the drawback to modify significantly the structure of the ordered mesoporous support during the washing-drying step (decrease of the average pore diameter of ca. 10 Å and of the surface area of ca. 30 %). In order to circumvent this problem, various washing-drying procedures were investigated. Washing with ethanol followed by drying under vacuum at 30°C was shown to be the most appropriate procedure since it allows to preserve the structure of the support and the high dispersion of the metallic phase.