Atomic and Electronic Structure of Pt/TiO 2 Catalysts and Their Relationship to Catalytic Activity.

Understanding the nature of the interaction between a metal and support, which is known as the metal-support interaction, in supported metal catalysts is crucial to design catalysts with desired properties. Here, we have developed model Pt/TiO 2 catalysts based on the deposition of colloidal Pt nanoparticles and studied their atomic and electronic structures before and after a postdeposition treatment that induces catalytic activity using aberration-corrected scanning transmission electron microscopy, electron energy loss spectroscopy, and first-principles calculations. Direct contact between Pt nanoparticles and TiO 2 is realized after the postdeposition treatment, which is accompanied by the formation of a Ti 3+ state on the TiO 2 surface close to the Pt nanoparticles and a Pt δ+ state on the Pt nanoparticles. The origin of these two states and their effect on the catalytic properties are discussed. These findings pave the way for a comprehensive understanding of metal-support interactions in supported metal catalysts.