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

Abstract

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 oC. 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 °C. Forms of ionic Pt2+ with different coordination with oxygen ensure the activity of catalysts starting at temperatures above 100 °C. Finally, small metallic clusters occupy an intermediate position, providing activity above 0 °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.