Incorporation of Ag on stable Pt/CeO2 for low-temperature active and high-temperature stable CO oxidation catalyst

Advanced engine technologies and environmental restrictions require new-generation automotive catalysts to be low-temperature (LT) active and high-temperature (HT) stable simultaneously. Here, incorporation of Ag over high temperature (800 °C) treated Pt/CeO 2 was applied to address the challenge. Strong Pt-O-Ce bonds in Pt/CeO 2 helped improve thermal stability dramatically. Detailed reaction kinetics analysis indicated Eley-Rideal (ER) mechanism for Ag/CeO 2 catalysts and Mars-van Krevelen (Mvk) mechanism for both Pt/CeO 2 and Ag/Pt/CeO 2 catalyst. After calcined at 800 °C, CO adsorbed on ionic Pt site could be readily oxidized by neighbouring oxygen species at a temperature as low as 132 °C over Ag/Pt/CeO 2 , about 60 °C lower than Pt/CeO 2 and Ag/CeO 2 . Raman spectroscopy and XPS results suggested that incorporation of Ag created more oxygen defects over Pt/CeO 2 and oxygen species on Ag nanoparticles might be more active than bare Pt/CeO 2 which would enhance the low-temperature activity for Ag/Pt/CeO 2 . It might be an effective and cost-efficient approach to develop new catalysts for vehicle emission oxidation.