Insights into formation of Pt species in Pt/CeO2 catalysts: Effect of treatment conditions and metal-support interaction

The features of the formation of Pt species on the CeO2 surface from adsorbed [PtCl6-yOy] complexes in Pt/CeO2 catalysts depending on the Pt content (0.5, 1.0 and 2.0 wt.%) and treatment conditions (direct Pt precursor reduction, oxidative and reductive treatments) are studied by XRD, CO pulse chemisorption, H-2-TPR, UV-vis DRS, and Raman spectroscopy. The temperature of oxidative decomposition of the Pt precursor is shown to be the key factor that defines the state and size of the Pt species formed. High pretreatment temperature (500 degrees C) provides Pt incorporation into ceria lattice and yields smaller Pt particles after reduction providing strong Pt-CeO2 interaction, while the reduction of the samples dried at 120 degrees C results in the pronounced agglomeration of the formed Pt species to yield Pt particles weakly bonded with the ceria.