Decomposition of Acetic Acid on Model Pt/CeO2 Catalysts: The Effect of Surface Crowding

Abstract

Adsorption and decomposition of acetic acid were studied by means of synchrotron radiation photoelectron spectroscopy, resonant photoemission spectroscopy, and temperature-programmed desorption on Pt/CeO2(111) model catalysts prepared on Cu(111). Reference experiments under identical conditions were performed on stoichiometric CeO2(111), partially reduced CeO2–x, and oxygen pre-exposed O/Pt/CeO2(111)/Cu(111). The principal species formed on all samples during adsorption of acetic acid at 150 K were acetate and molecularly adsorbed acetic acid. On the basis of the differences in the splitting between the methyl and carboxyl/carboxylate groups in the C 1s spectra, we identified the adsorption sites for acetate and molecularly adsorbed acetic acid on Pt/CeO2. During annealing, we detected an increase in the concentration of acetate on CeO2(111) support exclusively in the presence of supported Pt particles. The effect is caused by the decomposition of molecularly adsorbed acetic acid on Pt particles followed ...