Temperature-Dependent Change in Shape of Platinum Nanoparticles Supported on CeO₂during Catalytic Reactions

Abstract

The temperature dependence of the shape of Pt nanoparticles supported on CeO2 for CO oxidation was investigated using environmental transmission electron microscopy. Pt nanoparticles in CO/air become round at room temperature (when catalytic activity is low), while they become partially faceted at elevated temperature (when the catalytic activity is high). Based on a comparison between the shapes of the Pt nanoparticles in vacuum, N2, O2, CO, and CO/air at room temperature, 100, and 200 °C, we propose that the change in shape of the Pt nanoparticles is induced by the adsorption of CO molecules and O atoms.