(765d) Structural and Kinetic Study of CO Oxidation on Single Atom Pt/CeO2

We report CO oxidation kinetics, density functional theory (DFT) calculations and in-situ/operando characterization of CeO₂ supported Pt single atoms to identify the Pt active complex and reaction mechanism. The Pt single atoms supported on CeO₂ were synthesized by atom trapping and characterized by microcalorimetry of CO and O₂ adsorption, aberration corrected scanning transmission electron microscopy, in-situ aberration corrected high resolution transmission electron microscopy, in-situ infrared spectroscopy and operando x-ray absorption spectroscopy. We identified the Pt anchoring site on CeO₂ step sites using in-situ/operando EXAFS and the results show that the active Pt complex is generated under CO oxidation reaction conditions. A proposed CO oxidation reaction mechanism will be presented based on the measured kinetics, DFT calculations and in-situ/operando DRIFTS and EXAFS. Additionally, the effect of CO and O₂ pulses at different temperatures on the Pt stability, local coordination and activity for CO oxidation will be presented.