Promoting oxidation of high concentration CO via strong metal support interaction in unreduced Pt-based catalysts

Despite the excellent CO catalytic performance of Pt 0 , it tends to suffer oxidation in real high-temperature environments, leading to decrease in activity. Therefore, it is necessary to study the catalytic performance of Pt-based catalysts in their unreduced state. In this study, the structure-activity relationship of high concentration CO oxidation over unreduced platinum supported catalysts (Pt/CeO 2 , Pt/TiO 2 , Pt/SnO 2 , Pt/ZrO 2 , Pt/La 2 O 3 ) were investigated. The results indicate that due to the strong interaction between Pt and Ce, the valence changes of support element Ce facilitate the formation of redox pairs of Pt 2+ /Pt 4+ and Ce 3+ /Ce 4+ at the Pt-Ce interface, culminating in a catalytic activity superior to that of other catalysts. Furthermore, the 18 O 2 isotope experiment achieved quantification of different lattice oxygens. Surface cycle lattice oxygen in the Pt/CeO 2 , possessing the highest Turnover Frequency (4.75 ×10 −3 s −1 ), accounts for optimum catalytic activity. Both Mars-van Krevelen (M-K) mechanism and Langmuir-Hinshelwood (L-H) mechanism coexist in the CO catalytic oxidation , but the former predominates the reaction. The contribution proportion of the M-K mechanism decreases in the order of Pt/CeO 2 (83 %) > Pt/TiO 2 (79 %) > Pt/SnO 2 (76 %) > Pt/ZrO 2 (73 %) > Pt/La 2 O 3 (70 %), which corresponds to the activity results. • Unreduced Pt supported catalysts were used for high-concentration CO oxidation. • Stronger Pt and Ce interaction improves the catalytic activity. • Mars-van Krevelen mechanism predominates in CO oxidation. • 18 O 2 isotope experiment achieved quantification of different lattice oxygens. • Higher TOF of surface cycling lattice oxygen leads to better activity.