Low-Temperature CO Oxidation by the Pt/CeO2 Based Catalysts

This review analyzes the literature data and the results of studies of the Pt/CeO2-based catalysts that are capable of providing the low-temperature CO oxidation (LTO CO). The review summarizes the catalytic characteristics and the main properties of Pt/CeO2-based catalysts necessary for the low-temperature oxidation at T<50 degrees C. Analysis of the literature data on the use of physical methods of investigation and their correlation with the activity of Pt/CeO2 catalysts allowed us to conclude that the main active forms of platinum are small metallic clusters, single atoms Pt2+-SA and oxide clusters PtOx interacting with ceria nanoparticles. It has been established that the most active forms are PtOx clusters, which provide a high reaction rate in the temperature range from -50 to +50 degrees C. Forms of ionic Pt2+ with different coordination with oxygen ensure the activity of catalysts starting at temperatures above 100 degrees C. Finally, small metallic clusters occupy an intermediate position, providing activity above 0 degrees C, but their instability and gradual transition to the oxidized state Pt2+/PtOx are noted. At the conclusion of the review, the results of mathematical modeling demonstrate the correct kinetics description of the low-temperature CO oxidation based on the Mars-van Krevelen and associative mechanisms.